485BPOS

Registration Nos. 033-29697/811-5833

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933/X/

Post-Effective Amendment No. 83/X/

and/or

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940 /X/

Amendment No. 79/X/

T. ROWE PRICE INSTITUTIONAL INTERNATIONAL FUNDS, INC.

Exact Name of Registrant as Specified in Charter

100 East Pratt Street, Baltimore, Maryland 21202
Address of Principal Executive Offices

410-345-2000
Registrant’s Telephone Number, Including Area Code

David Oestreicher

100 East Pratt Street, Baltimore, Maryland 21202
Name and Address of Agent for Service

It is proposed that this filing will become effective (check appropriate box):

/X/Immediately upon filing pursuant to paragraph (b)

//On (date) pursuant to paragraph (b)

//60 days after filing pursuant to paragraph (a)(1)

//On (date) pursuant to paragraph (a)(1)

//75 days after filing pursuant to paragraph (a)(2)

//On (date) pursuant to paragraph (a)(2) of Rule 485

If appropriate, check the following box:

//This post-effective amendment designates a new effective date for a previously filed post-effective amendment.

Page 2

EXHIBITS

Exhibit	Exhibit No.
XBRL Instance Document	EX-101.INS
XBRL Taxonomy Extension Schema Document	EX-101.SCH
XBRL Taxonomy Extension Calculation Linkbase Document	EX-101.CAL
XBRL Taxonomy Extension Definition Linkbase Document	EX-101.DEF
XBRL Taxonomy Extension Labels Linkbase Document	EX-101.LAB
XBRL Taxonomy Extension Presentation Linkbase Document	EX-101.PRE

Page 3

Signatures

Pursuant to the requirements of the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, the Registrant certifies that it meets all of the requirements for effectiveness of this Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, duly authorized, in the City of Baltimore, State of Maryland, this March 12, 2019.

T. ROWE PRICE INSTITUTIONAL INTERNATIONAL FUNDS, INC.

/s/David Oestreicher

By:David Oestreicher

Director and Executive Vice President

Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed below by the following persons in the capacities and on the dates indicated:

Signature	Title	Date
/s/David Oestreicher	Director (Principal Executive Officer)	March 12, 2019
David Oestreicher	and Executive Vice President
/s/Catherine D. Mathews	Treasurer	March 12, 2019
Catherine D. Mathews	(Principal Financial Officer)
	and Vice President
*
Teresa Bryce Bazemore	Director	March 12, 2019
*
Ronald J. Daniels	Director	March 12, 2019
*
Bruce W. Duncan	Director	March 12, 2019
*
Robert J. Gerrard, Jr.	Chairman of the Board	March 12, 2019
	and Director
*
Paul F. McBride	Director	March 12, 2019
*
Cecilia E. Rouse	Director	March 12, 2019
*
John G. Schreiber	Director	March 12, 2019

Page 4

/s/Robert W. Sharps	Director and Vice President	March 12, 2019
Robert W. Sharps
*/s/David Oestreicher	Attorney-In-Fact	March 12, 2019
David Oestreicher

Page 5

T. ROWE PRICE BALANCED FUND, INC.

T. ROWE PRICE BLUE CHIP GROWTH FUND, INC.

T. ROWE PRICE CAPITAL APPRECIATION FUND, INC.

T. ROWE PRICE CAPITAL APPRECIATION & INCOME FUND, INC.

T. ROWE PRICE CAPITAL OPPORTUNITY FUND, INC.

T. ROWE PRICE COMMUNICATIONS & TECHNOLOGY FUND, INC.

T. ROWE PRICE CORPORATE INCOME FUND, INC.

T. ROWE PRICE CREDIT OPPORTUNITIES FUND, INC.

T. ROWE PRICE DIVERSIFIED MID-CAP GROWTH FUND, INC.

T. ROWE PRICE DIVIDEND GROWTH FUND, INC.

T. ROWE PRICE EQUITY INCOME FUND, INC.

T. ROWE PRICE EQUITY SERIES, INC.

T. ROWE PRICE FINANCIAL SERVICES FUND, INC.

T. ROWE PRICE FIXED INCOME SERIES, INC.

T. ROWE PRICE FLOATING RATE FUND, INC.

T. ROWE PRICE GLOBAL ALLOCATION FUND, INC.

T. ROWE PRICE GLOBAL MULTI-SECTOR BOND FUND, INC.

T. ROWE PRICE GLOBAL REAL ESTATE FUND, INC.

T. ROWE PRICE GLOBAL TECHNOLOGY FUND, INC.

T. ROWE PRICE GNMA FUND, INC.

T. ROWE PRICE GOVERNMENT MONEY FUND, INC.

T. ROWE PRICE GROWTH & INCOME FUND, INC.

T. ROWE PRICE GROWTH STOCK FUND, INC.

T. ROWE PRICE HEALTH SCIENCES FUND, INC.

T. ROWE PRICE HIGH YIELD FUND, INC.

T. ROWE PRICE INDEX TRUST, INC.

T. ROWE PRICE INFLATION PROTECTED BOND FUND, INC.

T. ROWE PRICE INSTITUTIONAL EQUITY FUNDS, INC.

T. ROWE PRICE INSTITUTIONAL INCOME FUNDS, INC.

T. ROWE PRICE INSTITUTIONAL INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERMEDIATE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERNATIONAL INDEX FUND, INC.

T. ROWE PRICE INTERNATIONAL SERIES, INC.

T. ROWE PRICE LIMITED DURATION INFLATION FOCUSED BOND FUND, INC.

T. ROWE PRICE MID-CAP GROWTH FUND, INC.

T. ROWE PRICE MID-CAP VALUE FUND, INC.

T. ROWE PRICE MULTI-SECTOR ACCOUNT PORTFOLIOS, INC.

T. ROWE PRICE MULTI-STRATEGY TOTAL RETURN FUND, INC.

T. ROWE PRICE NEW AMERICA GROWTH FUND, INC.
T. ROWE PRICE NEW ERA FUND, INC.

T. ROWE PRICE NEW HORIZONS FUND, INC.

T. ROWE PRICE NEW INCOME FUND, INC.

T. ROWE PRICE PERSONAL STRATEGY FUNDS, INC.

T. ROWE PRICE QUANTITATIVE MANAGEMENT FUNDS, INC.

T. ROWE PRICE REAL ASSETS FUND, INC.

T. ROWE PRICE REAL ESTATE FUND, INC.

T. ROWE PRICE RESERVE INVESTMENT FUNDS, INC.

T. ROWE PRICE RETIREMENT FUNDS, INC.

T. ROWE PRICE SCIENCE & TECHNOLOGY FUND, INC.

Page 6

T. ROWE PRICE SHORT-TERM BOND FUND, INC.

T. ROWE PRICE SMALL-CAP STOCK FUND, INC.

T. ROWE PRICE SMALL-CAP VALUE FUND, INC.

T. ROWE PRICE SPECTRUM FUND, INC.

T. ROWE PRICE STATE TAX-FREE FUNDS, INC.

T. ROWE PRICE SUMMIT FUNDS, INC.

T. ROWE PRICE SUMMIT MUNICIPAL FUNDS, INC.

T. ROWE PRICE TAX-EFFICIENT FUNDS, INC.

T. ROWE PRICE TAX-EXEMPT MONEY FUND, INC.

T. ROWE PRICE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE TAX-FREE INCOME FUND, INC.

T. ROWE PRICE TAX-FREE SHORT-INTERMEDIATE FUND, INC.

T. ROWE PRICE TOTAL RETURN FUND, INC.

T. ROWE PRICE U.S. BOND ENHANCED INDEX FUND, INC.

T. ROWE PRICE U.S. LARGE-CAP CORE FUND, INC.

T. ROWE PRICE U.S. TREASURY FUNDS, INC.

T. ROWE PRICE VALUE FUND, INC.

POWER OF ATTORNEY

RESOLVED, that the Corporation does hereby constitute and authorize Darrell N. Braman, Margery K. Neale, and David Oestreicher, and each of them individually, their true and lawful attorneys and agents to take any and all action and execute any and all instruments which said attorneys and agents may deem necessary or advisable to enable the Corporation to comply with the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, and any rules, regulations, orders or other requirements of the United States Securities and Exchange Commission thereunder, in connection with the registration under the Securities Act of 1933, as amended, of shares of the Corporation, to be offered by the Corporation, and the registration of the Corporation under the Investment Company Act of 1940, as amended, including specifically, but without limitation of the foregoing, power and authority to sign the name of the Corporation on its behalf, and to sign the names of each of such directors and officers on his or her behalf as such director or officer to any (i) Registration Statement on Form N-1A or N-14 of the Corporation filed with the Securities and Exchange Commission under the Securities Act of 1933, as amended; (ii) Registration Statement on Form N-1A or N-14 of the Corporation under the Investment Company Act of 1940, as amended; (iii) amendment or supplement (including, but not limited to, Post-Effective Amendments adding additional series or classes of the Corporation) to said Registration Statement; and (iv) instruments or documents filed or to be filed as a part of or in connection with such Registration Statement, including Articles Supplementary, Articles of Amendment, and other instruments with respect to the Articles of Incorporation of the Corporation.

IN WITNESS WHEREOF, the above named Corporations have caused these presents to be signed and the same attested by its Assistant Secretary, each thereunto duly authorized by its Board of Directors, and each of the undersigned has hereunto set his or her hand and seal as of the day set opposite his or her name.

Page 7

ALL CORPORATIONS /s/David Oestreicher
David Oestreicher /s/Catherine D. Mathews	Executive Vice President (Principal Executive Officer) Director	July 25, 2018
Catherine D. Mathews /s/Teresa Bryce Bazemore	Treasurer (Principal Financial Officer) Vice President	July 25, 2018
Teresa Bryce Bazemore /s/Ronald J. Daniels	Director	July 25, 2018
Ronald J. Daniels /s/Bruce W. Duncan	Director	July 25, 2018
Bruce W. Duncan /s/Robert J. Gerrard, Jr.	Director	July 25, 2018
Robert J. Gerrard, Jr. /s/Paul F. McBride	Director	July 25, 2018
Paul F. McBride /s/Cecilia E. Rouse	Director	July 25, 2018
Cecilia E. Rouse /s/John G. Schreiber	Director	July 25, 2018
John G. Schreiber /s/Mark R. Tercek	Director	July 25, 2018
Mark R. Tercek	Director	July 25, 2018

(Signatures Continued)

Page 8

ROBERT W. SHARPS, Director

T. ROWE PRICE BALANCED FUND, INC.

T. ROWE PRICE BLUE CHIP GROWTH FUND, INC.

T. ROWE PRICE CAPITAL APPRECIATION FUND, INC.

T. ROWE PRICE CAPITAL APPRECIATION & INCOME FUND, INC.

T. ROWE PRICE CAPITAL OPPORTUNITY FUND, INC.

T. ROWE PRICE COMMUNICATIONS & TECHNOLOGY FUND, INC.

T. ROWE PRICE DIVERSIFIED MID-CAP GROWTH FUND, INC.

T. ROWE PRICE DIVIDEND GROWTH FUND, INC.

T. ROWE PRICE EQUITY INCOME FUND, INC.

T. ROWE PRICE EQUITY SERIES, INC.

T. ROWE PRICE FINANCIAL SERVICES FUND, INC.

T. ROWE PRICE GLOBAL ALLOCATION FUND, INC.

T. ROWE PRICE GLOBAL REAL ESTATE FUND, INC.

T. ROWE PRICE GLOBAL TECHNOLOGY FUND, INC.

T. ROWE PRICE GROWTH & INCOME FUND, INC.

T. ROWE PRICE GROWTH STOCK FUND, INC.

T. ROWE PRICE HEALTH SCIENCES FUND, INC.

T. ROWE INDEX TRUST, INC.

T. ROWE PRICE INSTITUTIONAL EQUITY FUNDS, INC.

T. ROWE PRICE INSTITUTIONAL INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERNATIONAL INDEX FUND, INC.

T. ROWE PRICE INTERNATIONAL SERIES, INC.

T. ROWE PRICE MID-CAP GROWTH FUND, INC.

T. ROWE PRICE MID-CAP VALUE FUND, INC.

T. ROWE PRICE MULTI-STRATEGY TOTAL RETURN FUND, INC.

T. ROWE PRICE NEW AMERICA GROWTH FUND, INC.

T. ROWE PRICE NEW ERA FUND, INC.

T. ROWE PRICE NEW HORIZONS FUND, INC.

T. ROWE PRICE PERSONAL STRATEGY FUNDS, INC.

T. ROWE PRICE QUANTITATIVE MANAGEMENT FUNDS, INC.

T. ROWE PRICE REAL ASSETS FUND, INC.

T. ROWE PRICE REAL ESTATE FUND, INC.

T. ROWE PRICE RETIREMENT FUNDS, INC.

T. ROWE PRICE SCIENCE & TECHNOLOGY FUND, INC.

T. ROWE PRICE SMALL-CAP STOCK FUND, INC.

T. ROWE PRICE SMALL-CAP VALUE FUND, INC.

T. ROWE PRICE SPECTRUM FUND, INC.

T. ROWE PRICE TAX-EFFICIENT FUNDS, INC.

T. ROWE PRICE U.S. LARGE-CAP CORE FUND, INC.

T. ROWE PRICE VALUE FUND, INC.

/s/Robert W. Sharps

Robert W. Sharps July 25, 2018

(Signatures Continued)

Page 9

EDWARD A. WIESE, Director

T. ROWE PRICE CORPORATE INCOME FUND, INC.

T. ROWE PRICE CREDIT OPPORTUNITIES FUND, INC.

T. ROWE PRICE FIXED INCOME SERIES, INC.

T. ROWE PRICE FLOATING RATE FUND, INC.

T. ROWE PRICE GLOBAL MULTI-SECTOR BOND FUND, INC.

T. ROWE PRICE GNMA FUND, INC.

T. ROWE PRICE GOVERNMENT MONEY FUND, INC.

T. ROWE PRICE HIGH YIELD FUND, INC.

T. ROWE PRICE INSTITUTIONAL INCOME FUNDS, INC.

T. ROWE PRICE INFLATION PROTECTED BOND FUND, INC.

T. ROWE PRICE INTERMEDIATE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE LIMITED DURATION INFLATION FOCUSED BOND FUND, INC.

T. ROWE PRICE MULTI-SECTOR ACCOUNT PORTFOLIOS, INC.

T. ROWE PRICE NEW INCOME FUND, INC.

T. ROWE PRICE RESERVE INVESTMENT FUNDS, INC.

T. ROWE PRICE SHORT-TERM BOND FUND, INC.

T. ROWE PRICE STATE TAX-FREE FUNDS, INC.

T. ROWE PRICE SUMMIT FUNDS, INC.

T. ROWE PRICE SUMMIT MUNICIPAL FUNDS, INC.

T. ROWE PRICE TAX-EXEMPT MONEY FUND, INC.

T. ROWE PRICE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE TAX-FREE INCOME FUND, INC.

T. ROWE PRICE TAX-FREE SHORT-INTERMEDIATE FUND, INC.

T. ROWE PRICE TOTAL RETURN FUND, INC.

T. ROWE PRICE U.S. BOND ENHANCED INDEX FUND, INC.

T. ROWE PRICE U.S. TREASURY FUNDS, INC.

/s/Edward A. Wiese

Edward A. Wiese July 25, 2018

(Signatures Continued)

Page 10

ATTEST:

/s/Shannon Hofher Rauser

Shannon Hofher Rauser, Assistant Secretary

Page 11

T. ROWE PRICE CORPORATE INCOME FUND, INC.

T. ROWE PRICE CREDIT OPPORTUNITIES FUND, INC.

T. ROWE PRICE FIXED INCOME SERIES, INC.

T. ROWE PRICE FLOATING RATE FUND, INC.

T. ROWE PRICE GLOBAL MULTI-SECTOR BOND FUND, INC.

T. ROWE PRICE GNMA FUND, INC.

T. ROWE PRICE GOVERNMENT MONEY FUND, INC.

T. ROWE PRICE HIGH YIELD FUND, INC.

T. ROWE PRICE INSTITUTIONAL INCOME FUNDS, INC.

T. ROWE PRICE INFLATION PROTECTED BOND FUND, INC.

T. ROWE PRICE INTERMEDIATE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE LIMITED DURATION INFLATION FOCUSED BOND FUND, INC.

T. ROWE PRICE MULTI-SECTOR ACCOUNT PORTFOLIOS, INC.

T. ROWE PRICE NEW INCOME FUND, INC.

T. ROWE PRICE RESERVE INVESTMENT FUNDS, INC.

T. ROWE PRICE SHORT-TERM BOND FUND, INC.

T. ROWE PRICE STATE TAX-FREE FUNDS, INC.

T. ROWE PRICE SUMMIT FUNDS, INC.

T. ROWE PRICE SUMMIT MUNICIPAL FUNDS, INC.

T. ROWE PRICE TAX-EXEMPT MONEY FUND, INC.

T. ROWE PRICE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE TAX-FREE INCOME FUND, INC.

T. ROWE PRICE TAX-FREE SHORT-INTERMEDIATE FUND, INC.

T. ROWE PRICE TOTAL RETURN FUND, INC.

T. ROWE PRICE U.S. BOND ENHANCED INDEX FUND, INC.

T. ROWE PRICE U.S. TREASURY FUNDS, INC.

POWER OF ATTORNEY

RESOLVED, that the Corporation does hereby constitute and authorize Darrell N. Braman, Margery K. Neale, and David Oestreicher, and each of them individually, their true and lawful attorneys and agents to take any and all action and execute any and all instruments which said attorneys and agents may deem necessary or advisable to enable the Corporation to comply with the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, and any rules, regulations, orders or other requirements of the United States Securities and Exchange Commission thereunder, in connection with the registration under the Securities Act of 1933, as amended, of shares of the Corporation, to be offered by the Corporation, and the registration of the Corporation under the Investment Company Act of 1940, as amended, including specifically, but without limitation of the foregoing, power and authority to sign the name of the Corporation on its behalf, and to sign the names of each of such directors and officers on his or her behalf as such director or officer to any (i) Registration Statement on Form N-1A or N-14 of the Corporation filed with the Securities and Exchange Commission under the Securities Act of 1933, as amended; (ii) Registration Statement on Form N-1A or N-14 of the Corporation under the Investment Company Act of 1940, as amended; (iii) amendment or supplement (including, but not limited to, Post-Effective Amendments adding additional series or classes of the Corporation) to said Registration Statement; and (iv) instruments or documents filed or to be filed as a part of or in connection with such Registration Statement, including Articles Supplementary, Articles of Amendment, and other instruments with respect to the Articles of Incorporation of the Corporation.

Page 12

IN WITNESS WHEREOF, the above named Corporations have caused these presents to be signed and the same attested by its Assistant Secretary, each thereunto duly authorized by its Board of Directors, and each of the undersigned has hereunto set his or her hand and seal as of the day set opposite his or her name.

/s/Robert W. Sharps
Robert W. Sharps, Director	Date: January 1, 2019

ATTEST:

/s/Darrell N. Braman

Darrell N. Braman, Secretary

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	485BPOS
Document Period End Date	dei_DocumentPeriodEndDate	Oct. 31, 2018
Registrant Name	dei_EntityRegistrantName	T. Rowe Price Institutional International Funds, Inc.
Central Index Key	dei_EntityCentralIndexKey	0000852254
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Feb. 27, 2019
Document Effective Date	dei_DocumentEffectiveDate	Mar. 01, 2019
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
Entity Inv Company Type	dei_EntityInvCompanyType	N-1A

XML

T. Rowe Price Institutional Africa & Middle East Fund

T. ROWE PRICE<br/><br/>Institutional Africa & Middle East Fund<br/><br/>SUMMARY

Investment Objective

The fund seeks long-term growth of capital by investing primarily in the common stocks of companies located (or with primary operations) in Africa and the Middle East.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund<br/><br/><b>Shareholder fees (fees paid directly from your investment)</b>

Shareholder Fees	T. Rowe Price Institutional Africa & Middle East Fund T. Rowe Price Institutional Africa & Middle East Fund
Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)	2.00%	[1]

<b>Annual fund operating expenses<br/> (expenses that you pay each year as a<br/> percentage of the value of your investment)</b>

Annual Fund Operating Expenses	T. Rowe Price Institutional Africa & Middle East Fund T. Rowe Price Institutional Africa & Middle East Fund
Management fees	1.00%
Other expenses	0.18%
Total annual fund operating expenses	1.18%

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional Africa & Middle East Fund | T. Rowe Price Institutional Africa & Middle East Fund | USD ($)	120	375	649	1,432

Portfolio Turnover

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 49.6% of the average value of its portfolio.

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

The fund normally invests at least 80% of its net assets (including any borrowings for investment purposes) in African and Middle Eastern companies. For purposes of determining whether the fund invests at least 80% of its net assets in African and Middle Eastern companies, the fund relies on the country assigned to a security by MSCI Inc. or another unaffiliated data provider. The fund expects to primarily invest in common stocks and participation notes (P-notes) linked to common stocks of companies located (or with primary operations) in Africa and the Middle East. The countries in which the fund normally invests include, but are not limited to, the following:

• Primary Emphasis: Bahrain, Egypt, Jordan, Kenya, Kuwait, Lebanon, Morocco, Nigeria, Oman, Qatar, Saudi Arabia, South Africa, and United Arab Emirates.

• Others: Algeria, Angola, Botswana, Ghana, Ivory Coast, Mauritius, Mozambique, Namibia, Niger Republic, Rwanda, Senegal, Syria, Tanzania, Tunisia, Uganda, Zambia, and Zimbabwe.

The fund is “nondiversified,” meaning it may invest a greater portion of its assets in a single company and own more of the company’s voting securities than is permissible for a “diversified” fund. The fund’s portfolio is expected to be composed of investments in about 50 to 80 different companies, although the number could vary depending on market conditions. The fund may purchase the stocks of companies of any size. While most assets will be invested directly in common stocks, the fund may gain exposure to common stocks by purchasing P-notes that offer a return linked to a particular underlying common stock. P-notes are primarily used to invest indirectly in certain stocks that trade in a market that restricts foreign investors, such as the fund, from investing directly in that market. The fund may make substantial investments (at times more than 25% of its total assets) in telecommunications and banking companies in various African and Middle Eastern countries.

While the adviser invests with an awareness of the outlook for certain industry sectors and individual countries within the region, the adviser’s decision-making process focuses on bottom-up stock selection. Country allocation is driven largely by stock selection, though the adviser may limit investments in markets or industries that appear to have poor overall prospects.

Security selection reflects a growth style. The adviser relies on a global team of investment analysts dedicated to in-depth fundamental research in an effort to identify companies capable of achieving and sustaining above-average, long-term earnings growth. The adviser seeks to purchase stocks of companies at reasonable prices in relation to present or anticipated earnings, cash flow, or book value.

In selecting investments, the adviser generally favors companies with one or more of the following characteristics:

• leading or improving market position;

• attractive business niche;

• attractive or improving franchise or industry position;

• seasoned management;

• stable or improving earnings and/or cash flow; and

• sound or improving balance sheet.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S.

Emerging markets risks The risks of international investing are heightened for securities of issuers in emerging market countries. Emerging market countries tend to have economic structures that are less diverse and mature, and political systems that are less stable, than those of developed countries. In addition to all of the risks of investing in international developed markets, emerging markets are more susceptible to governmental interference, local taxes being imposed on international investments, restrictions on gaining access to the fund’s investments, and less efficient trading markets with lower overall liquidity.

Frontier markets generally have smaller economies and less mature capital markets than emerging markets. As a result, the risks of investing in emerging market countries are magnified in frontier market countries. Frontier markets are more susceptible to abrupt changes in currency values, have less mature markets and settlement practices, and can have lower trading volumes that could lead to greater price volatility and illiquidity.

P-note risks To the extent the fund invests in P-notes, it is subject to certain risks in addition to the risks normally associated with a direct investment in the underlying foreign securities the P-note seeks to replicate. As the purchaser of a P-note, the fund is relying on the creditworthiness of the counterparty issuing the P-note and does not have the same rights under a P-note as it would as a shareholder of the underlying issuer. Therefore, if a counterparty becomes insolvent, the fund could lose the total value of its investment in the P-note. In addition, there is no assurance that there will be a trading market for a P-note or that the trading price of a P-note will equal the value of the underlying security.

Geographic concentration risks Because the fund concentrates its investments in a particular geographic region, the fund’s performance is closely tied to the social, political, and economic conditions within that region. Political developments and changes in regulatory, tax, or economic policy in particular countries within the region could significantly affect the markets in those countries as well as the entire region. As a result, the fund is likely to be more volatile than more geographically diverse international funds.

Many African and Middle Eastern countries have histories of dictatorships, political and military unrest, and financial troubles, and their markets should be considered extremely volatile even when compared to those of other emerging market countries. Many of these countries tend to be highly reliant on exporting oil and other commodities so their economies can be significantly impacted by fluctuations in commodity prices and the global demand for certain commodities.

Risks of investing in Saudi Arabia Because the ability of foreign investors (such as the fund) to invest in Saudi Arabian issuers is still relatively new and untested, such ability could be restricted or revoked by the Saudi Arabian government at any time, and unforeseen risks could materialize due to foreign ownership in such securities. The economy of Saudi Arabia is dominated by petroleum exports. As a result, a sustained decrease in petroleum prices would have a negative impact on all aspects of the Saudi Arabian economy. Political instability in Saudi Arabia, or even the broader Middle East region, could adversely impact the economy of Saudi Arabia.

Risks of investing in South Africa Investing in securities of South African issuers involves significant risks, including legal, political, and economic risks specific to South Africa. South Africa has a history of social unrest and governmental interference, which could lead to increased volatility. In addition, South Africa’s economy is heavily dependent on agriculture and mining and is therefore more susceptible to market events and regulatory developments impacting the commodity markets.

Industry risks Because the fund may invest significantly in telecommunications and banking companies, the fund is more susceptible to adverse developments affecting such companies and may perform poorly during a downturn in one or more of the industries that heavily impact telecommunications and banking companies. Telecommunications companies can be adversely affected by, among other things, changes in government regulation, intense competition, and rapid obsolescence of products and services due to technological innovations or changing consumer preferences. Banks and other financial services companies can be adversely affected by, among other things, regulatory changes, interest rate movements, the availability of capital and cost to borrow, and the rate of debt defaults.

Nondiversification risks As a nondiversified fund, the fund has the ability to invest a larger percentage of its assets in the securities of a smaller number of issuers than a diversified fund. As a result, poor performance by a single issuer could adversely affect fund performance more than if the fund were invested in a larger number of issuers. The fund’s share price can be expected to fluctuate more than that of a comparable diversified fund.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Market capitalization risks Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies often have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies. Larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and they may be less capable of responding quickly to competitive challenges and industry changes.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

<b>INSTITUTIONAL AFRICA & MIDDLE EAST FUND</b><br/>Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	30.11%	Worst Quarter	9/30/15	-15.82%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

<b>Average Annual Total Returns <br/><br/>Periods ended<br/>December 31, 2018 </b>

Average Annual Total Returns - T. Rowe Price Institutional Africa & Middle East Fund		1 Year	5 Years	10 Years		Inception date
T. Rowe Price Institutional Africa & Middle East Fund		(8.61%)	1.50%	7.36%		Apr. 30, 2008
T. Rowe Price Institutional Africa & Middle East Fund | Returns after taxes on distributions		(9.95%)	0.19%	6.33%		Apr. 30, 2008
T. Rowe Price Institutional Africa & Middle East Fund | Returns after taxes on distributions and sales of fund returns		(4.01%)	1.04%	5.81%		Apr. 30, 2008
MSCI Arabian Markets & Africa 10/40 Investable Market Index Net (reflects no deduction for fees or expenses)	[1]	(8.71%)	(0.22%)	2.22%	[2]	Nov. 30, 2010
MSCI Arabian Markets & Africa 10/40 Investable Market Index (reflects no deduction for fees, expenses, or taxes)		(8.33%)	0.13%	2.53%	[2]	Nov. 30, 2010
S&P Emerging/Frontier ME & Africa BMI ex IL (reflects no deduction for fees, expenses, or taxes)		(9.17%)	0.14%	6.22%
Combined Index Portfolio Net (reflects no deduction for fees or expenses)	[3]	(8.71%)	(0.22%)	6.27%
Lipper Emerging Markets Funds Average		(16.27%)	0.37%	7.53%

Updated performance information is available through troweprice.com.

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[1] Effective July 1, 2018, the MSCI Arabian Markets & Africa 10/40 Investable Market Index Net replaced the MSCI Arabian Markets & Africa 10/40 Investable Market Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

[2] Return since 11/30/10.

[3] Combined Index Portfolio Net is an unmanaged linked performance portfolio composed of: 100% S&P IFCG Africa & Middle East Index Net (excluding Saudi Arabia and Israel) through 6/30/09 (prior to 9/1/08, the index excluded Kuwait); 100% MSCI Arabian Markets & Africa Index Net from 7/1/09 through 9/29/10; 100% S&P Emerging/Frontier ME & Africa BMI ex IL Net from 9/30/10 through 12/31/17; and 100% MSCI Arabian Markets & Africa 10/40 Investable Market Index Net from 1/1/18 forward.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional International Funds, Inc.

Prospectus Date

rr_ProspectusDate

Mar. 01, 2019

T. Rowe Price Institutional Africa & Middle East Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. ROWE PRICE<br/><br/>Institutional Africa & Middle East Fund<br/><br/>SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks long-term growth of capital by investing primarily in the common stocks of companies located (or with primary operations) in Africa and the Middle East.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Fees and Expenses of the Fund<br/><br/><b>Shareholder fees (fees paid directly from your investment)</b>

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

<b>Annual fund operating expenses<br/> (expenses that you pay each year as a<br/> percentage of the value of your investment)</b>

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 49.6% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

49.60%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The fund normally invests at least 80% of its net assets (including any borrowings for investment purposes) in African and Middle Eastern companies. For purposes of determining whether the fund invests at least 80% of its net assets in African and Middle Eastern companies, the fund relies on the country assigned to a security by MSCI Inc. or another unaffiliated data provider. The fund expects to primarily invest in common stocks and participation notes (P-notes) linked to common stocks of companies located (or with primary operations) in Africa and the Middle East. The countries in which the fund normally invests include, but are not limited to, the following:

• Primary Emphasis: Bahrain, Egypt, Jordan, Kenya, Kuwait, Lebanon, Morocco, Nigeria, Oman, Qatar, Saudi Arabia, South Africa, and United Arab Emirates.

• Others: Algeria, Angola, Botswana, Ghana, Ivory Coast, Mauritius, Mozambique, Namibia, Niger Republic, Rwanda, Senegal, Syria, Tanzania, Tunisia, Uganda, Zambia, and Zimbabwe.

The fund is “nondiversified,” meaning it may invest a greater portion of its assets in a single company and own more of the company’s voting securities than is permissible for a “diversified” fund. The fund’s portfolio is expected to be composed of investments in about 50 to 80 different companies, although the number could vary depending on market conditions. The fund may purchase the stocks of companies of any size. While most assets will be invested directly in common stocks, the fund may gain exposure to common stocks by purchasing P-notes that offer a return linked to a particular underlying common stock. P-notes are primarily used to invest indirectly in certain stocks that trade in a market that restricts foreign investors, such as the fund, from investing directly in that market. The fund may make substantial investments (at times more than 25% of its total assets) in telecommunications and banking companies in various African and Middle Eastern countries.

While the adviser invests with an awareness of the outlook for certain industry sectors and individual countries within the region, the adviser’s decision-making process focuses on bottom-up stock selection. Country allocation is driven largely by stock selection, though the adviser may limit investments in markets or industries that appear to have poor overall prospects.

Security selection reflects a growth style. The adviser relies on a global team of investment analysts dedicated to in-depth fundamental research in an effort to identify companies capable of achieving and sustaining above-average, long-term earnings growth. The adviser seeks to purchase stocks of companies at reasonable prices in relation to present or anticipated earnings, cash flow, or book value.

In selecting investments, the adviser generally favors companies with one or more of the following characteristics:

• leading or improving market position;

• attractive business niche;

• attractive or improving franchise or industry position;

• seasoned management;

• stable or improving earnings and/or cash flow; and

• sound or improving balance sheet.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S.

Emerging markets risks The risks of international investing are heightened for securities of issuers in emerging market countries. Emerging market countries tend to have economic structures that are less diverse and mature, and political systems that are less stable, than those of developed countries. In addition to all of the risks of investing in international developed markets, emerging markets are more susceptible to governmental interference, local taxes being imposed on international investments, restrictions on gaining access to the fund’s investments, and less efficient trading markets with lower overall liquidity.

Frontier markets generally have smaller economies and less mature capital markets than emerging markets. As a result, the risks of investing in emerging market countries are magnified in frontier market countries. Frontier markets are more susceptible to abrupt changes in currency values, have less mature markets and settlement practices, and can have lower trading volumes that could lead to greater price volatility and illiquidity.

P-note risks To the extent the fund invests in P-notes, it is subject to certain risks in addition to the risks normally associated with a direct investment in the underlying foreign securities the P-note seeks to replicate. As the purchaser of a P-note, the fund is relying on the creditworthiness of the counterparty issuing the P-note and does not have the same rights under a P-note as it would as a shareholder of the underlying issuer. Therefore, if a counterparty becomes insolvent, the fund could lose the total value of its investment in the P-note. In addition, there is no assurance that there will be a trading market for a P-note or that the trading price of a P-note will equal the value of the underlying security.

Geographic concentration risks Because the fund concentrates its investments in a particular geographic region, the fund’s performance is closely tied to the social, political, and economic conditions within that region. Political developments and changes in regulatory, tax, or economic policy in particular countries within the region could significantly affect the markets in those countries as well as the entire region. As a result, the fund is likely to be more volatile than more geographically diverse international funds.

Many African and Middle Eastern countries have histories of dictatorships, political and military unrest, and financial troubles, and their markets should be considered extremely volatile even when compared to those of other emerging market countries. Many of these countries tend to be highly reliant on exporting oil and other commodities so their economies can be significantly impacted by fluctuations in commodity prices and the global demand for certain commodities.

Risks of investing in Saudi Arabia Because the ability of foreign investors (such as the fund) to invest in Saudi Arabian issuers is still relatively new and untested, such ability could be restricted or revoked by the Saudi Arabian government at any time, and unforeseen risks could materialize due to foreign ownership in such securities. The economy of Saudi Arabia is dominated by petroleum exports. As a result, a sustained decrease in petroleum prices would have a negative impact on all aspects of the Saudi Arabian economy. Political instability in Saudi Arabia, or even the broader Middle East region, could adversely impact the economy of Saudi Arabia.

Risks of investing in South Africa Investing in securities of South African issuers involves significant risks, including legal, political, and economic risks specific to South Africa. South Africa has a history of social unrest and governmental interference, which could lead to increased volatility. In addition, South Africa’s economy is heavily dependent on agriculture and mining and is therefore more susceptible to market events and regulatory developments impacting the commodity markets.

Industry risks Because the fund may invest significantly in telecommunications and banking companies, the fund is more susceptible to adverse developments affecting such companies and may perform poorly during a downturn in one or more of the industries that heavily impact telecommunications and banking companies. Telecommunications companies can be adversely affected by, among other things, changes in government regulation, intense competition, and rapid obsolescence of products and services due to technological innovations or changing consumer preferences. Banks and other financial services companies can be adversely affected by, among other things, regulatory changes, interest rate movements, the availability of capital and cost to borrow, and the rate of debt defaults.

Nondiversification risks As a nondiversified fund, the fund has the ability to invest a larger percentage of its assets in the securities of a smaller number of issuers than a diversified fund. As a result, poor performance by a single issuer could adversely affect fund performance more than if the fund were invested in a larger number of issuers. The fund’s share price can be expected to fluctuate more than that of a comparable diversified fund.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Market capitalization risks Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies often have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies. Larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and they may be less capable of responding quickly to competitive challenges and industry changes.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Risk Nondiversified Status [Text]

rr_RiskNondiversifiedStatus

Nondiversification risks As a nondiversified fund, the fund has the ability to invest a larger percentage of its assets in the securities of a smaller number of issuers than a diversified fund. As a result, poor performance by a single issuer could adversely affect fund performance more than if the fund were invested in a larger number of issuers. The fund’s share price can be expected to fluctuate more than that of a comparable diversified fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund.<br/><br/>The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.<br/><br/>The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

<b>troweprice.com</b>

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

<b>INSTITUTIONAL AFRICA & MIDDLE EAST FUND</b><br/>Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	30.11%	Worst Quarter	9/30/15	-15.82%

Performance Table Heading

rr_PerformanceTableHeading

<b>Average Annual Total Returns <br/><br/>Periods ended<br/>December 31, 2018 </b>

Performance Table Market Index Changed

rr_PerformanceTableMarketIndexChanged

Effective July 1, 2018, the MSCI Arabian Markets & Africa 10/40 Investable Market Index Net replaced the MSCI Arabian Markets & Africa 10/40 Investable Market Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional Africa & Middle East Fund | T. Rowe Price Institutional Africa & Middle East Fund

Risk/Return:

rr_RiskReturnAbstract

Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)

rr_RedemptionFeeOverRedemption

2.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.18%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.18%

1 year

rr_ExpenseExampleYear01

$ 120

3 years

rr_ExpenseExampleYear03

375

5 years

rr_ExpenseExampleYear05

649

10 years

rr_ExpenseExampleYear10

$ 1,432

2009

rr_AnnualReturn2009

27.65%

2010

rr_AnnualReturn2010

17.92%

2011

rr_AnnualReturn2011

(15.95%)

2012

rr_AnnualReturn2012

20.29%

2013

rr_AnnualReturn2013

24.08%

2014

rr_AnnualReturn2014

10.54%

2015

rr_AnnualReturn2015

(19.15%)

2016

rr_AnnualReturn2016

6.57%

2017

rr_AnnualReturn2017

23.75%

2018

rr_AnnualReturn2018

(8.61%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

<b>Best Quarter</b>

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

30.11%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

<b>Worst Quarter</b>

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2015

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(15.82%)

1 Year

rr_AverageAnnualReturnYear01

(8.61%)

5 Years

rr_AverageAnnualReturnYear05

1.50%

10 Years

rr_AverageAnnualReturnYear10

7.36%

Inception date

rr_AverageAnnualReturnInceptionDate

Apr. 30, 2008

T. Rowe Price Institutional Africa & Middle East Fund | Returns after taxes on distributions | T. Rowe Price Institutional Africa & Middle East Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(9.95%)

5 Years

rr_AverageAnnualReturnYear05

0.19%

10 Years

rr_AverageAnnualReturnYear10

6.33%

Inception date

rr_AverageAnnualReturnInceptionDate

Apr. 30, 2008

T. Rowe Price Institutional Africa & Middle East Fund | Returns after taxes on distributions and sales of fund returns | T. Rowe Price Institutional Africa & Middle East Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(4.01%)

5 Years

rr_AverageAnnualReturnYear05

1.04%

10 Years

rr_AverageAnnualReturnYear10

5.81%

Inception date

rr_AverageAnnualReturnInceptionDate

Apr. 30, 2008

T. Rowe Price Institutional Africa & Middle East Fund | MSCI Arabian Markets & Africa 10/40 Investable Market Index Net (reflects no deduction for fees or expenses)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(8.71%)

^[2]

5 Years

rr_AverageAnnualReturnYear05

(0.22%)

^[2]

10 Years

rr_AverageAnnualReturnYear10

2.22%

^[2],[3]

Inception date

rr_AverageAnnualReturnInceptionDate

Nov. 30, 2010

^[2]

T. Rowe Price Institutional Africa & Middle East Fund | MSCI Arabian Markets & Africa 10/40 Investable Market Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(8.33%)

5 Years

rr_AverageAnnualReturnYear05

0.13%

10 Years

rr_AverageAnnualReturnYear10

2.53%

^[3]

Inception date

rr_AverageAnnualReturnInceptionDate

Nov. 30, 2010

T. Rowe Price Institutional Africa & Middle East Fund | S&P Emerging/Frontier ME & Africa BMI ex IL (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(9.17%)

5 Years

rr_AverageAnnualReturnYear05

0.14%

10 Years

rr_AverageAnnualReturnYear10

6.22%

T. Rowe Price Institutional Africa & Middle East Fund | Combined Index Portfolio Net (reflects no deduction for fees or expenses)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(8.71%)

^[4]

5 Years

rr_AverageAnnualReturnYear05

(0.22%)

^[4]

10 Years

rr_AverageAnnualReturnYear10

6.27%

^[4]

T. Rowe Price Institutional Africa & Middle East Fund | Lipper Emerging Markets Funds Average

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(16.27%)

5 Years

rr_AverageAnnualReturnYear05

0.37%

10 Years

rr_AverageAnnualReturnYear10

7.53%

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[2] Effective July 1, 2018, the MSCI Arabian Markets & Africa 10/40 Investable Market Index Net replaced the MSCI Arabian Markets & Africa 10/40 Investable Market Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

[3] Return since 11/30/10.

[4] Combined Index Portfolio Net is an unmanaged linked performance portfolio composed of: 100% S&P IFCG Africa & Middle East Index Net (excluding Saudi Arabia and Israel) through 6/30/09 (prior to 9/1/08, the index excluded Kuwait); 100% MSCI Arabian Markets & Africa Index Net from 7/1/09 through 9/29/10; 100% S&P Emerging/Frontier ME & Africa BMI ex IL Net from 9/30/10 through 12/31/17; and 100% MSCI Arabian Markets & Africa 10/40 Investable Market Index Net from 1/1/18 forward.

XML

T. Rowe Price Institutional Emerging Markets Equity Fund

T. ROWE PRICE<br/><br/>Institutional Emerging Markets Equity Fund<br/><br/>SUMMARY

Investment Objective

The fund seeks long-term growth of capital through investments primarily in the common stocks of companies located (or with primary operations) in emerging markets.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund<br/><br/> <b>Shareholder fees (fees paid directly from your investment)</b>

Shareholder Fees	T. Rowe Price Institutional Emerging Markets Equity Fund T. Rowe Price Institutional Emerging Markets Equity Fund
Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)	2.00%	[1]

<b>Annual fund operating expenses<br/>(expenses that you pay each year as a<br/>percentage of the value of your investment)</b>

Annual Fund Operating Expenses	T. Rowe Price Institutional Emerging Markets Equity Fund T. Rowe Price Institutional Emerging Markets Equity Fund
Management fees	1.10%
Other expenses
Total annual fund operating expenses	1.10%

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional Emerging Markets Equity Fund | T. Rowe Price Institutional Emerging Markets Equity Fund | USD ($)	112	350	606	1,340

Portfolio Turnover

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 14.0% of the average value of its portfolio.

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

The fund normally invests at least 80% of its net assets (including any borrowings for investment purposes) in emerging market companies. For purposes of determining whether the fund invests at least 80% of its net assets in emerging market companies, the fund relies on MSCI Inc. to determine which countries are considered emerging markets and relies on the country assigned to a security by MSCI Inc. or another unaffiliated data provider. The fund considers frontier markets to be a subset of emerging markets and any investments in frontier markets will be counted toward the fund’s 80% investment policy. The fund expects to primarily invest in common stocks of companies located (or with primary operations) in emerging markets in Latin America, Asia, Europe, Africa, and the Middle East. The countries in which the fund normally invests include, but are not limited to, the following:

• Asia: China, India, Indonesia, Malaysia, Pakistan, Philippines, South Korea, Sri Lanka, Taiwan, Thailand, and Vietnam.

• Latin America: Argentina, Belize, Brazil, Chile, Colombia, Mexico, Panama, Peru, and Venezuela.

• Europe: Croatia, Czech Republic, Estonia, Greece, Hungary, Kazakhstan, Latvia, Lithuania, Poland, Romania, Russia, Slovakia, Slovenia, Turkey, and Ukraine.

• Africa and the Middle East: Bahrain, Botswana, Egypt, Jordan, Kenya, Kuwait, Lebanon, Mauritius, Morocco, Nigeria, Oman, Qatar, Saudi Arabia, South Africa, Tunisia, United Arab Emirates, and Zimbabwe.

The fund may purchase the stocks of companies of any size. While the adviser invests with an awareness of the global economic backdrop and the adviser’s outlook for certain industries, sectors, and individual countries, the adviser’s decision-making process focuses on bottom-up stock selection. Country allocation is driven largely by stock selection, though the adviser may limit investments in markets or industries that appear to have poor overall prospects. The fund may at times invest significantly in China.

Security selection reflects a growth style. The adviser relies on a global team of investment analysts dedicated to in-depth fundamental research in an effort to identify companies capable of achieving and sustaining above-average, long-term earnings growth. The adviser seeks to purchase stocks of companies at reasonable prices in relation to present or anticipated earnings, cash flow, or book value. The fund may at times invest significantly in certain sectors, such as the financials sector.

In selecting investments, the adviser generally favors companies with one or more of the following characteristics:

• leading or improving market position;

• attractive business niche;

• attractive or improving franchise or industry position;

• seasoned management;

• stable or improving earnings and/or cash flow; and

• sound or improving balance sheet.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S.

Emerging markets risks The risks of international investing are heightened for securities of issuers in emerging market countries. Emerging market countries tend to have economic structures that are less diverse and mature, and political systems that are less stable, than those of developed countries. In addition to all of the risks of investing in international developed markets, emerging markets are more susceptible to governmental interference, local taxes being imposed on international investments, restrictions on gaining access to the fund’s investments, and less efficient trading markets with lower overall liquidity.

Frontier markets generally have smaller economies and less mature capital markets than emerging markets. As a result, the risks of investing in emerging market countries are magnified in frontier market countries. Frontier markets are more susceptible to abrupt changes in currency values, have less mature markets and settlement practices, and can have lower trading volumes that could lead to greater price volatility and illiquidity.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Market capitalization risks Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies often have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies. Larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and they may be less capable of responding quickly to competitive challenges and industry changes.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the financials sector. Companies in the financials sector may be adversely impacted by, among other things, regulatory changes, economic conditions, interest rates, credit rating downgrades, and decreased liquidity in credit markets.

Risks of investing in China The fund may invest significantly in China. The Chinese government has historically exercised significant control over China’s economy and its financial markets through, among other things, its monetary policies and allocation of resources, management of currency exchange rates, preferential treatment or restrictions relating to industries deemed sensitive to national interests, and limitations on foreign ownership of Chinese securities. Although economic reforms have liberalized trade policy and reduced government control, changes in these policies or increased government intervention could adversely impact affected industries or companies. China’s currency, which historically has been managed in a tight range relative to the U.S. dollar, may in the future be subject to greater uncertainty as Chinese authorities change the policies that determine the official currency exchange rate. Additionally, the Chinese economy is highly dependent on the exportation of products and services, and could experience a significant slowdown due to a reduction in global demand for Chinese exports, contraction in spending on domestic goods by Chinese consumers, and trade or political disputes with China’s major trading partners. The U.S. and China have been imposing tariffs on certain goods traded between the countries. Heightened trade tensions between the U.S. and China, and the institution of additional tariffs or trade barriers between China and any of its key trading partners, including the U.S., could have a significant adverse impact on the Chinese economy.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

<b>INSTITUTIONAL EMERGING MARKETS EQUITY FUND</b><br/>Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	42.94%	Worst Quarter	9/30/11	-23.07%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

<b>Average Annual Total Returns<br/><br/>Periods ended<br/>December 31, 2018 </b>

Average Annual Total Returns - T. Rowe Price Institutional Emerging Markets Equity Fund		1 Year	5 Years	10 Years	Inception date
T. Rowe Price Institutional Emerging Markets Equity Fund		(16.03%)	3.91%	9.65%	Oct. 31, 2002
T. Rowe Price Institutional Emerging Markets Equity Fund | Returns after taxes on distributions		(16.08%)	3.87%	9.62%	Oct. 31, 2002
T. Rowe Price Institutional Emerging Markets Equity Fund | Returns after taxes on distributions and sales of fund returns		(9.15%)	3.19%	8.14%	Oct. 31, 2002
MSCI Emerging Markets Index Net (reflects no deduction for fees or expenses)	[1]	(14.57%)	1.65%	8.02%
MSCI Emerging Markets Index (reflects no deduction for fees, expenses, or taxes)		(14.24%)	2.03%	8.39%
Lipper Emerging Markets Funds Average		(16.27%)	0.37%	7.53%

Updated performance information is available through troweprice.com.

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[1] Effective July 1, 2018, the MSCI Emerging Markets Index Net replaced the MSCI Emerging Markets Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional International Funds, Inc.

Prospectus Date

rr_ProspectusDate

Mar. 01, 2019

T. Rowe Price Institutional Emerging Markets Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. ROWE PRICE<br/><br/>Institutional Emerging Markets Equity Fund<br/><br/>SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks long-term growth of capital through investments primarily in the common stocks of companies located (or with primary operations) in emerging markets.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Fees and Expenses of the Fund<br/><br/> <b>Shareholder fees (fees paid directly from your investment)</b>

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

<b>Annual fund operating expenses<br/>(expenses that you pay each year as a<br/>percentage of the value of your investment)</b>

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 14.0% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

14.00%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The fund normally invests at least 80% of its net assets (including any borrowings for investment purposes) in emerging market companies. For purposes of determining whether the fund invests at least 80% of its net assets in emerging market companies, the fund relies on MSCI Inc. to determine which countries are considered emerging markets and relies on the country assigned to a security by MSCI Inc. or another unaffiliated data provider. The fund considers frontier markets to be a subset of emerging markets and any investments in frontier markets will be counted toward the fund’s 80% investment policy. The fund expects to primarily invest in common stocks of companies located (or with primary operations) in emerging markets in Latin America, Asia, Europe, Africa, and the Middle East. The countries in which the fund normally invests include, but are not limited to, the following:

• Asia: China, India, Indonesia, Malaysia, Pakistan, Philippines, South Korea, Sri Lanka, Taiwan, Thailand, and Vietnam.

• Latin America: Argentina, Belize, Brazil, Chile, Colombia, Mexico, Panama, Peru, and Venezuela.

• Europe: Croatia, Czech Republic, Estonia, Greece, Hungary, Kazakhstan, Latvia, Lithuania, Poland, Romania, Russia, Slovakia, Slovenia, Turkey, and Ukraine.

• Africa and the Middle East: Bahrain, Botswana, Egypt, Jordan, Kenya, Kuwait, Lebanon, Mauritius, Morocco, Nigeria, Oman, Qatar, Saudi Arabia, South Africa, Tunisia, United Arab Emirates, and Zimbabwe.

The fund may purchase the stocks of companies of any size. While the adviser invests with an awareness of the global economic backdrop and the adviser’s outlook for certain industries, sectors, and individual countries, the adviser’s decision-making process focuses on bottom-up stock selection. Country allocation is driven largely by stock selection, though the adviser may limit investments in markets or industries that appear to have poor overall prospects. The fund may at times invest significantly in China.

Security selection reflects a growth style. The adviser relies on a global team of investment analysts dedicated to in-depth fundamental research in an effort to identify companies capable of achieving and sustaining above-average, long-term earnings growth. The adviser seeks to purchase stocks of companies at reasonable prices in relation to present or anticipated earnings, cash flow, or book value. The fund may at times invest significantly in certain sectors, such as the financials sector.

In selecting investments, the adviser generally favors companies with one or more of the following characteristics:

• leading or improving market position;

• attractive business niche;

• attractive or improving franchise or industry position;

• seasoned management;

• stable or improving earnings and/or cash flow; and

• sound or improving balance sheet.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S.

Emerging markets risks The risks of international investing are heightened for securities of issuers in emerging market countries. Emerging market countries tend to have economic structures that are less diverse and mature, and political systems that are less stable, than those of developed countries. In addition to all of the risks of investing in international developed markets, emerging markets are more susceptible to governmental interference, local taxes being imposed on international investments, restrictions on gaining access to the fund’s investments, and less efficient trading markets with lower overall liquidity.

Frontier markets generally have smaller economies and less mature capital markets than emerging markets. As a result, the risks of investing in emerging market countries are magnified in frontier market countries. Frontier markets are more susceptible to abrupt changes in currency values, have less mature markets and settlement practices, and can have lower trading volumes that could lead to greater price volatility and illiquidity.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Market capitalization risks Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies often have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies. Larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and they may be less capable of responding quickly to competitive challenges and industry changes.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the financials sector. Companies in the financials sector may be adversely impacted by, among other things, regulatory changes, economic conditions, interest rates, credit rating downgrades, and decreased liquidity in credit markets.

Risks of investing in China The fund may invest significantly in China. The Chinese government has historically exercised significant control over China’s economy and its financial markets through, among other things, its monetary policies and allocation of resources, management of currency exchange rates, preferential treatment or restrictions relating to industries deemed sensitive to national interests, and limitations on foreign ownership of Chinese securities. Although economic reforms have liberalized trade policy and reduced government control, changes in these policies or increased government intervention could adversely impact affected industries or companies. China’s currency, which historically has been managed in a tight range relative to the U.S. dollar, may in the future be subject to greater uncertainty as Chinese authorities change the policies that determine the official currency exchange rate. Additionally, the Chinese economy is highly dependent on the exportation of products and services, and could experience a significant slowdown due to a reduction in global demand for Chinese exports, contraction in spending on domestic goods by Chinese consumers, and trade or political disputes with China’s major trading partners. The U.S. and China have been imposing tariffs on certain goods traded between the countries. Heightened trade tensions between the U.S. and China, and the institution of additional tariffs or trade barriers between China and any of its key trading partners, including the U.S., could have a significant adverse impact on the Chinese economy.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund. <br/><br/>The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.<br/><br/>The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

<b>troweprice.com</b>

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

<b>INSTITUTIONAL EMERGING MARKETS EQUITY FUND</b><br/>Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	42.94%	Worst Quarter	9/30/11	-23.07%

Performance Table Heading

rr_PerformanceTableHeading

<b>Average Annual Total Returns<br/><br/>Periods ended<br/>December 31, 2018 </b>

Performance Table Market Index Changed

rr_PerformanceTableMarketIndexChanged

Effective July 1, 2018, the MSCI Emerging Markets Index Net replaced the MSCI Emerging Markets Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional Emerging Markets Equity Fund | T. Rowe Price Institutional Emerging Markets Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)

rr_RedemptionFeeOverRedemption

2.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

1.10%

Other expenses

rr_OtherExpensesOverAssets

Total annual fund operating expenses

rr_ExpensesOverAssets

1.10%

1 year

rr_ExpenseExampleYear01

$ 112

3 years

rr_ExpenseExampleYear03

350

5 years

rr_ExpenseExampleYear05

606

10 years

rr_ExpenseExampleYear10

$ 1,340

2009

rr_AnnualReturn2009

86.38%

2010

rr_AnnualReturn2010

19.25%

2011

rr_AnnualReturn2011

(18.63%)

2012

rr_AnnualReturn2012

20.49%

2013

rr_AnnualReturn2013

(4.84%)

2014

rr_AnnualReturn2014

1.70%

2015

rr_AnnualReturn2015

(11.47%)

2016

rr_AnnualReturn2016

12.17%

2017

rr_AnnualReturn2017

42.87%

2018

rr_AnnualReturn2018

(16.03%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

<b>Best Quarter</b>

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

42.94%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

<b>Worst Quarter</b>

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(23.07%)

1 Year

rr_AverageAnnualReturnYear01

(16.03%)

5 Years

rr_AverageAnnualReturnYear05

3.91%

10 Years

rr_AverageAnnualReturnYear10

9.65%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 31, 2002

T. Rowe Price Institutional Emerging Markets Equity Fund | Returns after taxes on distributions | T. Rowe Price Institutional Emerging Markets Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(16.08%)

5 Years

rr_AverageAnnualReturnYear05

3.87%

10 Years

rr_AverageAnnualReturnYear10

9.62%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 31, 2002

T. Rowe Price Institutional Emerging Markets Equity Fund | Returns after taxes on distributions and sales of fund returns | T. Rowe Price Institutional Emerging Markets Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(9.15%)

5 Years

rr_AverageAnnualReturnYear05

3.19%

10 Years

rr_AverageAnnualReturnYear10

8.14%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 31, 2002

T. Rowe Price Institutional Emerging Markets Equity Fund | MSCI Emerging Markets Index Net (reflects no deduction for fees or expenses)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(14.57%)

^[2]

5 Years

rr_AverageAnnualReturnYear05

1.65%

^[2]

10 Years

rr_AverageAnnualReturnYear10

8.02%

^[2]

T. Rowe Price Institutional Emerging Markets Equity Fund | MSCI Emerging Markets Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(14.24%)

5 Years

rr_AverageAnnualReturnYear05

2.03%

10 Years

rr_AverageAnnualReturnYear10

8.39%

T. Rowe Price Institutional Emerging Markets Equity Fund | Lipper Emerging Markets Funds Average

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(16.27%)

5 Years

rr_AverageAnnualReturnYear05

0.37%

10 Years

rr_AverageAnnualReturnYear10

7.53%

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[2] Effective July 1, 2018, the MSCI Emerging Markets Index Net replaced the MSCI Emerging Markets Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

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T. Rowe Price Institutional Frontier Markets Equity Fund

T. ROWE PRICE<br/><br/>Institutional Frontier Markets Equity Fund<br/><br/>SUMMARY

Investment Objective

The fund seeks long-term growth of capital.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund<br/><br/> <b>Shareholder fees (fees paid directly from your investment)</b>

Shareholder Fees	T. Rowe Price Institutional Frontier Markets Equity Fund T. Rowe Price Institutional Frontier Markets Equity Fund
Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)	2.00%	[1]

<b>Annual fund operating expenses<br/>(expenses that you pay each year as a<br/>percentage of the value of your investment)</b>

Annual Fund Operating Expenses	T. Rowe Price Institutional Frontier Markets Equity Fund T. Rowe Price Institutional Frontier Markets Equity Fund
Management fees	1.10%
Other expenses	0.51%
Acquired fund fees and expenses	0.01%
Total annual fund operating expenses	1.62%
Fee waiver/expense reimbursement	(0.23%)	[1]
Total annual fund operating expenses after fee waiver/expense reimbursement	1.39%	[1],[2]

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. The example also assumes that an expense limitation arrangement currently in place is not renewed; therefore, the figures have been adjusted to reflect fee waivers or expense reimbursements only in the periods for which the expense limitation arrangement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional Frontier Markets Equity Fund | T. Rowe Price Institutional Frontier Markets Equity Fund | USD ($)	142	465	837	1,882

Portfolio Turnover

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 55.6% of the average value of its portfolio.

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

The fund normally invests at least 80% of its net assets (including any borrowings for investment purposes) in equity securities and equity-related investments of companies that are located in, or that have economic ties to, countries considered to be frontier markets. For purposes of determining whether the fund invests at least 80% in frontier markets, the fund relies on the country assigned to a security by MSCI Inc. or another unaffiliated data provider. The fund may purchase securities issued by companies of any size, but typically seeks larger companies to the extent opportunities are available within frontier markets. The fund expects to make most of its investments in companies in frontier markets in Africa, the Middle East, Asia, Europe, and Latin America.

Frontier markets are those markets which are not as developed as emerging markets. The fund considers a country to be a frontier market if it is not included in the MSCI All Country World Index, which contains all of the countries that MSCI Inc. has classified as either a developed market or emerging market. The countries that are considered frontier markets may change over time based on how they are classified by MSCI Inc. The fund expects to typically seek investments in the frontier markets listed below (other countries may be added or listed countries may be removed):

• Africa and Middle East: Bahrain, Botswana, Ghana, Jordan, Kenya, Kuwait, Lebanon, Mauritius, Morocco, Namibia, Nigeria, Oman, Saudi Arabia, Tanzania, Tunisia, Uganda, Zambia, and Zimbabwe.

• Asia: Bangladesh, Cambodia, Pakistan, Sri Lanka, and Vietnam.

• Europe: Bosnia, Bulgaria, Croatia, Estonia, Georgia, Kazakhstan, Lithuania, Romania, Serbia, Slovenia, and Ukraine.

• Latin America: Argentina, Jamaica, Panama, and Trinidad & Tobago.

The fund is “nondiversified,” meaning it may invest a greater portion of its assets in a single company and own more of the company’s voting securities than is permissible for a “diversified” fund. Most of the fund’s assets will be invested directly in common stocks. The fund may also gain exposure to common stocks by purchasing participation notes (“P-notes”) that offer a return linked to a particular common stock. P-notes are primarily used to invest indirectly in certain stocks that trade in a market that restricts foreign investors, such as the fund, from investing directly in that market.

While the adviser invests with an awareness of the global economic backdrop and the adviser’s outlook for certain industries, sectors, and individual countries, the adviser’s decision-making process focuses on bottom-up stock selection. Country allocation is driven largely by stock selection, though the adviser may limit investments in markets or industries that appear to have poor overall prospects. The growth of certain frontier market countries relies heavily on the success of the banking industry. As a result, the fund expects to concentrate its investments (i.e., invest more than 25% of its net assets) in securities issued by banks and other financial services companies. The fund may at times invest significantly in certain countries or geographical regions, such as Argentina.

The adviser relies on a global team of investment analysts dedicated to in-depth fundamental research in an effort to identify quality companies with strong cash flows and sustainable growth potential, and does not emphasize either a growth or value bias when identifying potential investments. The fund’s investments may at times include securities of companies that are in the process of being privatized by a government, securities of companies that trade in unregulated over-the-counter markets or other types of unlisted securities markets, and unregistered securities issued in private placements. In managing the fund’s portfolio, the adviser principally employs a bottom-up approach to identify particular securities for investment. Research analysts conduct proprietary industry and company analysis to assess companies’ prospects while also considering macroeconomic factors that could limit opportunities in certain regions or frontier markets overall. The fund generally looks for companies with an attractive industry structure, compelling fundamentals, proven management team, and/or strong valuation upside.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

P-note risks To the extent the fund invests in P-notes, it is subject to certain risks in addition to the risks normally associated with a direct investment in the underlying foreign securities the P-note seeks to replicate. As the purchaser of a P-note, the fund is relying on the creditworthiness of the counterparty issuing the P-note and does not have the same rights under a P-note as it would as a shareholder of the underlying issuer. Therefore, if a counterparty becomes insolvent, the fund could lose the total value of its investment in the P-note. In addition, there is no assurance that there will be a trading market for a P-note or that the trading price of a P-note will equal the value of the underlying security.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S.

Frontier markets risks The risks of international investing are heightened for investments in emerging market and frontier market countries. Emerging and frontier market countries tend to have economic structures that are less diverse and mature, and political systems that are less stable, than those of developed market countries. In addition to all of the risks of investing in international developed markets, emerging and frontier markets tend to have less liquid and efficient trading markets and are more susceptible to governmental interference, local taxes being imposed on international investments, and restrictions on gaining access to sales proceeds. Frontier markets generally have smaller economies or less mature capital markets than emerging markets and, as a result, the risks typically associated with investing in emerging market countries are magnified in frontier countries. Adverse changes in currency values of frontier market countries may be severe and settlement procedures and custody services may prove inadequate in certain markets. The markets of frontier countries typically have low trading volumes and the potential for extreme price volatility and illiquidity. This volatility may be further increased by the actions of a few major investors. For example, a substantial increase or decrease in cash flows of mutual funds investing in these markets could significantly affect local stock prices and, therefore, the net asset value of the fund. All of these factors make investing in frontier countries significantly riskier than investing in other countries, including emerging market countries.

Risks of investing in Argentina Argentina has experienced high interest rates, economic volatility, inflation, currency devaluations and high unemployment rates. The economy is heavily dependent on exports and commodities. In addition, Argentina has previously defaulted on its debt and recently settled with holdout minority bondholders that demanded to be paid the full amount on the defaulted debt. Further defaults and related actions by Argentina may continue to impact the confidence of investors in Argentina, which could limit the government’s ability to borrow in the future.

Banking industry risks Because the fund invests significantly in banking and financial services companies, the fund is more susceptible to adverse developments affecting such companies and may perform poorly during a downturn in the banking industry. Banks and other financial services companies can be adversely affected by, among other things, regulatory changes, interest rate movements, the availability of capital and cost to borrow, and the rate of debt defaults. The oversight of banks in frontier markets may be ineffective and underdeveloped relative to more mature markets. In particular for frontier markets, the impact of future regulation on any individual bank, or on the financial services sector as a whole, can be very difficult to predict.

Nondiversification risks As a nondiversified fund, the fund has the ability to invest a larger percentage of its assets in the securities of a smaller number of issuers than a diversified fund. As a result, poor performance by a single issuer could adversely affect fund performance more than if the fund were invested in a larger number of issuers. The fund’s share price can be expected to fluctuate more than that of a comparable diversified fund.

Market capitalization risks The fund’s focus on large companies subjects the fund to the risks that larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and that they may be less capable of responding quickly to competitive challenges and industry changes. Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies typically have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

<b>INSTITUTIONAL FRONTIER MARKETS EQUITY FUND</b><br/>Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/17	8.59%	Worst Quarter	6/30/18	-15.49%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

<b>Average Annual Total Returns<br/><br/>Periods ended <br/>December 31, 2018 </b>

Average Annual Total Returns - T. Rowe Price Institutional Frontier Markets Equity Fund		1 Year	Since inception		Inception date
T. Rowe Price Institutional Frontier Markets Equity Fund		(19.63%)	(2.18%)		Sep. 22, 2014
T. Rowe Price Institutional Frontier Markets Equity Fund | Returns after taxes on distributions		(19.93%)	(2.44%)		Sep. 22, 2014
T. Rowe Price Institutional Frontier Markets Equity Fund | Returns after taxes on distributions and sale of fund shares		(11.36%)	(1.60%)		Sep. 22, 2014
MSCI Frontier Markets Index Net (reflects no deduction for fees or taxes)	[1]	(16.41%)	(3.96%)	[2]	Sep. 22, 2014
MSCI Frontier Markets Index (reflects no deduction for fees or taxes)		(16.20%)	(3.61%)	[2]	Sep. 22, 2014
Lipper Emerging Markets Funds Average		(16.27%)	(0.12%)	[3]	Sep. 30, 2014

Updated performance information is available through troweprice.com.

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[1] T. Rowe Price Associates, Inc., has agreed (through February 28, 2021) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the fund’s ratio of expenses to average daily net assets to exceed 1.35%. The agreement may be terminated at any time beyond February 28, 2021, with approval by the fund’s Board of Directors. Fees waived and expenses paid under this agreement (and a previous limitation of 1.35%) are subject to reimbursement to T. Rowe Price Associates, Inc., by the fund whenever the fund’s expense ratio is below 1.35%. However, no reimbursement will be made more than three years from the date such amounts were initially waived or reimbursed. The fund may only make repayments to T. Rowe Price Associates, Inc., if such repayment does not cause the fund’s expense ratio (after the repayment is taken into account) to exceed the lesser of: (1) the expense limitation in place at the time such amounts were waived; or (2) the fund’s current expense limitation.

[2] The figure shown in the fee table does not match the “Ratios to average net assets” shown in the Financial Highlights table, as those figures do not include acquired fund fees and expenses.

[1] Effective July 1, 2018, the MSCI Frontier Markets Index Net replaced the MSCI Frontier Markets Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

[2] Return since 9/22/14.

[3] Return since 9/30/14.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional International Funds, Inc.

Prospectus Date

rr_ProspectusDate

Mar. 01, 2019

T. Rowe Price Institutional Frontier Markets Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. ROWE PRICE<br/><br/>Institutional Frontier Markets Equity Fund<br/><br/>SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks long-term growth of capital.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Fees and Expenses of the Fund<br/><br/> <b>Shareholder fees (fees paid directly from your investment)</b>

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

<b>Annual fund operating expenses<br/>(expenses that you pay each year as a<br/>percentage of the value of your investment)</b>

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

February 28, 2021

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 55.6% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

55.60%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

The figure shown in the fee table does not match the “Ratios to average net assets” shown in the Financial Highlights table, as those figures do not include acquired fund fees and expenses.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. The example also assumes that an expense limitation arrangement currently in place is not renewed; therefore, the figures have been adjusted to reflect fee waivers or expense reimbursements only in the periods for which the expense limitation arrangement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The fund normally invests at least 80% of its net assets (including any borrowings for investment purposes) in equity securities and equity-related investments of companies that are located in, or that have economic ties to, countries considered to be frontier markets. For purposes of determining whether the fund invests at least 80% in frontier markets, the fund relies on the country assigned to a security by MSCI Inc. or another unaffiliated data provider. The fund may purchase securities issued by companies of any size, but typically seeks larger companies to the extent opportunities are available within frontier markets. The fund expects to make most of its investments in companies in frontier markets in Africa, the Middle East, Asia, Europe, and Latin America.

Frontier markets are those markets which are not as developed as emerging markets. The fund considers a country to be a frontier market if it is not included in the MSCI All Country World Index, which contains all of the countries that MSCI Inc. has classified as either a developed market or emerging market. The countries that are considered frontier markets may change over time based on how they are classified by MSCI Inc. The fund expects to typically seek investments in the frontier markets listed below (other countries may be added or listed countries may be removed):

• Africa and Middle East: Bahrain, Botswana, Ghana, Jordan, Kenya, Kuwait, Lebanon, Mauritius, Morocco, Namibia, Nigeria, Oman, Saudi Arabia, Tanzania, Tunisia, Uganda, Zambia, and Zimbabwe.

• Asia: Bangladesh, Cambodia, Pakistan, Sri Lanka, and Vietnam.

• Europe: Bosnia, Bulgaria, Croatia, Estonia, Georgia, Kazakhstan, Lithuania, Romania, Serbia, Slovenia, and Ukraine.

• Latin America: Argentina, Jamaica, Panama, and Trinidad & Tobago.

The fund is “nondiversified,” meaning it may invest a greater portion of its assets in a single company and own more of the company’s voting securities than is permissible for a “diversified” fund. Most of the fund’s assets will be invested directly in common stocks. The fund may also gain exposure to common stocks by purchasing participation notes (“P-notes”) that offer a return linked to a particular common stock. P-notes are primarily used to invest indirectly in certain stocks that trade in a market that restricts foreign investors, such as the fund, from investing directly in that market.

While the adviser invests with an awareness of the global economic backdrop and the adviser’s outlook for certain industries, sectors, and individual countries, the adviser’s decision-making process focuses on bottom-up stock selection. Country allocation is driven largely by stock selection, though the adviser may limit investments in markets or industries that appear to have poor overall prospects. The growth of certain frontier market countries relies heavily on the success of the banking industry. As a result, the fund expects to concentrate its investments (i.e., invest more than 25% of its net assets) in securities issued by banks and other financial services companies. The fund may at times invest significantly in certain countries or geographical regions, such as Argentina.

The adviser relies on a global team of investment analysts dedicated to in-depth fundamental research in an effort to identify quality companies with strong cash flows and sustainable growth potential, and does not emphasize either a growth or value bias when identifying potential investments. The fund’s investments may at times include securities of companies that are in the process of being privatized by a government, securities of companies that trade in unregulated over-the-counter markets or other types of unlisted securities markets, and unregistered securities issued in private placements. In managing the fund’s portfolio, the adviser principally employs a bottom-up approach to identify particular securities for investment. Research analysts conduct proprietary industry and company analysis to assess companies’ prospects while also considering macroeconomic factors that could limit opportunities in certain regions or frontier markets overall. The fund generally looks for companies with an attractive industry structure, compelling fundamentals, proven management team, and/or strong valuation upside.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

P-note risks To the extent the fund invests in P-notes, it is subject to certain risks in addition to the risks normally associated with a direct investment in the underlying foreign securities the P-note seeks to replicate. As the purchaser of a P-note, the fund is relying on the creditworthiness of the counterparty issuing the P-note and does not have the same rights under a P-note as it would as a shareholder of the underlying issuer. Therefore, if a counterparty becomes insolvent, the fund could lose the total value of its investment in the P-note. In addition, there is no assurance that there will be a trading market for a P-note or that the trading price of a P-note will equal the value of the underlying security.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S.

Frontier markets risks The risks of international investing are heightened for investments in emerging market and frontier market countries. Emerging and frontier market countries tend to have economic structures that are less diverse and mature, and political systems that are less stable, than those of developed market countries. In addition to all of the risks of investing in international developed markets, emerging and frontier markets tend to have less liquid and efficient trading markets and are more susceptible to governmental interference, local taxes being imposed on international investments, and restrictions on gaining access to sales proceeds. Frontier markets generally have smaller economies or less mature capital markets than emerging markets and, as a result, the risks typically associated with investing in emerging market countries are magnified in frontier countries. Adverse changes in currency values of frontier market countries may be severe and settlement procedures and custody services may prove inadequate in certain markets. The markets of frontier countries typically have low trading volumes and the potential for extreme price volatility and illiquidity. This volatility may be further increased by the actions of a few major investors. For example, a substantial increase or decrease in cash flows of mutual funds investing in these markets could significantly affect local stock prices and, therefore, the net asset value of the fund. All of these factors make investing in frontier countries significantly riskier than investing in other countries, including emerging market countries.

Risks of investing in Argentina Argentina has experienced high interest rates, economic volatility, inflation, currency devaluations and high unemployment rates. The economy is heavily dependent on exports and commodities. In addition, Argentina has previously defaulted on its debt and recently settled with holdout minority bondholders that demanded to be paid the full amount on the defaulted debt. Further defaults and related actions by Argentina may continue to impact the confidence of investors in Argentina, which could limit the government’s ability to borrow in the future.

Banking industry risks Because the fund invests significantly in banking and financial services companies, the fund is more susceptible to adverse developments affecting such companies and may perform poorly during a downturn in the banking industry. Banks and other financial services companies can be adversely affected by, among other things, regulatory changes, interest rate movements, the availability of capital and cost to borrow, and the rate of debt defaults. The oversight of banks in frontier markets may be ineffective and underdeveloped relative to more mature markets. In particular for frontier markets, the impact of future regulation on any individual bank, or on the financial services sector as a whole, can be very difficult to predict.

Nondiversification risks As a nondiversified fund, the fund has the ability to invest a larger percentage of its assets in the securities of a smaller number of issuers than a diversified fund. As a result, poor performance by a single issuer could adversely affect fund performance more than if the fund were invested in a larger number of issuers. The fund’s share price can be expected to fluctuate more than that of a comparable diversified fund.

Market capitalization risks The fund’s focus on large companies subjects the fund to the risks that larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and that they may be less capable of responding quickly to competitive challenges and industry changes. Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies typically have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Risk Nondiversified Status [Text]

rr_RiskNondiversifiedStatus

Nondiversification risks As a nondiversified fund, the fund has the ability to invest a larger percentage of its assets in the securities of a smaller number of issuers than a diversified fund. As a result, poor performance by a single issuer could adversely affect fund performance more than if the fund were invested in a larger number of issuers. The fund’s share price can be expected to fluctuate more than that of a comparable diversified fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund. <br/><br/>The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund. <br/><br/> The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

<b>troweprice.com</b>

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

<b>INSTITUTIONAL FRONTIER MARKETS EQUITY FUND</b><br/>Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/17	8.59%	Worst Quarter	6/30/18	-15.49%

Performance Table Heading

rr_PerformanceTableHeading

<b>Average Annual Total Returns<br/><br/>Periods ended <br/>December 31, 2018 </b>

Performance Table Market Index Changed

rr_PerformanceTableMarketIndexChanged

Effective July 1, 2018, the MSCI Frontier Markets Index Net replaced the MSCI Frontier Markets Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional Frontier Markets Equity Fund | T. Rowe Price Institutional Frontier Markets Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)

rr_RedemptionFeeOverRedemption

2.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

1.10%

Other expenses

rr_OtherExpensesOverAssets

0.51%

Acquired fund fees and expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.01%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.62%

Fee waiver/expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

(0.23%)

^[2]

Total annual fund operating expenses after fee waiver/expense reimbursement

rr_NetExpensesOverAssets

1.39%

^[2],[3]

1 year

rr_ExpenseExampleYear01

$ 142

3 years

rr_ExpenseExampleYear03

465

5 years

rr_ExpenseExampleYear05

837

10 years

rr_ExpenseExampleYear10

$ 1,882

2015

rr_AnnualReturn2015

(12.83%)

2016

rr_AnnualReturn2016

10.10%

2017

rr_AnnualReturn2017

31.69%

2018

rr_AnnualReturn2018

(19.63%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

<b>Best Quarter</b>

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2017

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

8.59%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

<b>Worst Quarter</b>

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2018

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(15.49%)

1 Year

rr_AverageAnnualReturnYear01

(19.63%)

Since inception

rr_AverageAnnualReturnSinceInception

(2.18%)

Inception date

rr_AverageAnnualReturnInceptionDate

Sep. 22, 2014

T. Rowe Price Institutional Frontier Markets Equity Fund | Returns after taxes on distributions | T. Rowe Price Institutional Frontier Markets Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(19.93%)

Since inception

rr_AverageAnnualReturnSinceInception

(2.44%)

Inception date

rr_AverageAnnualReturnInceptionDate

Sep. 22, 2014

T. Rowe Price Institutional Frontier Markets Equity Fund | Returns after taxes on distributions and sale of fund shares | T. Rowe Price Institutional Frontier Markets Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(11.36%)

Since inception

rr_AverageAnnualReturnSinceInception

(1.60%)

Inception date

rr_AverageAnnualReturnInceptionDate

Sep. 22, 2014

T. Rowe Price Institutional Frontier Markets Equity Fund | MSCI Frontier Markets Index Net (reflects no deduction for fees or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(16.41%)

^[4]

Since inception

rr_AverageAnnualReturnSinceInception

(3.96%)

^[4],[5]

Inception date

rr_AverageAnnualReturnInceptionDate

Sep. 22, 2014

^[4]

T. Rowe Price Institutional Frontier Markets Equity Fund | MSCI Frontier Markets Index (reflects no deduction for fees or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(16.20%)

Since inception

rr_AverageAnnualReturnSinceInception

(3.61%)

^[5]

Inception date

rr_AverageAnnualReturnInceptionDate

Sep. 22, 2014

T. Rowe Price Institutional Frontier Markets Equity Fund | Lipper Emerging Markets Funds Average

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(16.27%)

Since inception

rr_AverageAnnualReturnSinceInception

(0.12%)

^[6]

Inception date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2014

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[2] T. Rowe Price Associates, Inc., has agreed (through February 28, 2021) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the fund’s ratio of expenses to average daily net assets to exceed 1.35%. The agreement may be terminated at any time beyond February 28, 2021, with approval by the fund’s Board of Directors. Fees waived and expenses paid under this agreement (and a previous limitation of 1.35%) are subject to reimbursement to T. Rowe Price Associates, Inc., by the fund whenever the fund’s expense ratio is below 1.35%. However, no reimbursement will be made more than three years from the date such amounts were initially waived or reimbursed. The fund may only make repayments to T. Rowe Price Associates, Inc., if such repayment does not cause the fund’s expense ratio (after the repayment is taken into account) to exceed the lesser of: (1) the expense limitation in place at the time such amounts were waived; or (2) the fund’s current expense limitation.

[3] The figure shown in the fee table does not match the “Ratios to average net assets” shown in the Financial Highlights table, as those figures do not include acquired fund fees and expenses.

[4] Effective July 1, 2018, the MSCI Frontier Markets Index Net replaced the MSCI Frontier Markets Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

[5] Return since 9/22/14.

[6] Return since 9/30/14.

XML

T. Rowe Price Institutional Global Focused Growth Equity Fund

T. ROWE PRICE<br/><br/>Institutional Global Focused Growth Equity Fund<br/><br/>SUMMARY

Investment Objective

The fund seeks long-term growth of capital through investments primarily in the common stocks of established companies throughout the world, including the U.S.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund<br/><br/> <b>Shareholder fees (fees paid directly from your investment)</b>

Shareholder Fees	T. Rowe Price Institutional Global Focused Growth Equity Fund T. Rowe Price Institutional Global Focused Growth Equity Fund
Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)	2.00%	[1]

<b>Annual fund operating expenses<br/> (expenses that you pay each year as a<br/> percentage of the value of your investment)</b>

Annual Fund Operating Expenses	T. Rowe Price Institutional Global Focused Growth Equity Fund T. Rowe Price Institutional Global Focused Growth Equity Fund
Management fees	0.65%
Other expenses	0.52%
Total annual fund operating expenses	1.17%
Fee waiver/expense reimbursement	(0.42%)	[1]
Total annual fund operating expenses after fee waiver/expense reimbursement	0.75%	[1]

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. The example also assumes that an expense limitation arrangement currently in place is not renewed; therefore, the figures have been adjusted to reflect fee waivers or expense reimbursements only in the periods for which the expense limitation arrangement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional Global Focused Growth Equity Fund | T. Rowe Price Institutional Global Focused Growth Equity Fund | USD ($)	77	286	560	1,343

Portfolio Turnover

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 111.5% of the average value of its portfolio.

Investments, Risks, and Performance<br/><br/> Principal Investment Strategies

The fund seeks to be broadly diversified by investing in a variety of industries in developed and, to a lesser extent, emerging markets. The fund normally invests in at least five countries, one of which is the U.S. Under normal conditions, at least 80% of the fund’s net assets (including any borrowings for investment purposes) will be invested in stocks and at least 40% of the fund’s net assets will be invested in stocks of companies outside the U.S. (at least 30% if foreign market conditions are not favorable). While the fund has flexibility to purchase stocks of companies of any size, investments will typically focus on large- and mid-cap growth stocks. The fund may at times invest significantly in certain sectors, such as the information technology sector.

While the adviser invests with an awareness of the global economic backdrop and the adviser’s outlook for certain industries, sectors, and individual countries, the adviser’s decision-making process focuses on bottom-up stock selection. Country allocation is driven largely by stock selection, though the adviser may limit investments in markets or industries that appear to have poor overall prospects.

Security selection reflects a growth style. The adviser relies on a global team of investment analysts dedicated to in-depth fundamental research in an effort to identify companies capable of achieving and sustaining above-average, long-term earnings growth. The adviser seeks to purchase stocks of companies at reasonable prices in relation to present or anticipated earnings, cash flow, or book value.

In selecting investments, the adviser generally favors companies with one or more of the following characteristics:

• leading or improving market position;

• attractive business niche;

• attractive or improving franchise or industry position;

• seasoned management;

• stable or improving earnings and/or cash flow; and

• sound or improving balance sheet.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall asset allocation investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes and restrictions on gaining access to the fund’s investments.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Market capitalization risks The fund’s focus on large companies subjects the fund to the risks that larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and that they may be less capable of responding quickly to competitive challenges and industry changes. Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies typically have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the information technology sector. Companies in the information technology sector can be adversely affected by, among other things, intense competition, earnings disappointments, and rapid obsolescence of products and services due to technological innovations or changing consumer preferences.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

<b>INSTITUTIONAL GLOBAL FOCUSED GROWTH EQUITY FUND</b><br/>Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	22.81%	Worst Quarter	9/30/11	-19.37%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

<b>Average Annual Total Returns<br/><br/>Periods ended<br/>December 31, 2018</b>

Average Annual Total Returns - T. Rowe Price Institutional Global Focused Growth Equity Fund		1 Year	5 Years	10 Years	Inception date
T. Rowe Price Institutional Global Focused Growth Equity Fund		(4.19%)	9.06%	13.00%	Jun. 30, 2006
T. Rowe Price Institutional Global Focused Growth Equity Fund | Returns after taxes on distributions		(7.74%)	5.34%	10.99%	Jun. 30, 2006
T. Rowe Price Institutional Global Focused Growth Equity Fund | Returns after taxes on distributions and sale of fund shares		(0.71%)	6.43%	10.51%	Jun. 30, 2006
MSCI All Country World Index Net (reflects no deduction for fees, expenses, or taxes)	[1]	(9.41%)	4.26%	9.46%
MSCI All Country World Index (reflects no deduction for fees, expenses, or taxes)		(8.93%)	4.82%	10.05%
Lipper Global Multi-Cap Growth Funds Average		(8.58%)	4.63%	10.26%

Updated performance information is available through troweprice.com.

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[1] T. Rowe Price Associates, Inc., has agreed (through February 28, 2021) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the class’ ratio of expenses to average daily net assets to exceed 0.75%. The agreement may be terminated at any time beyond February 28, 2021, with approval by the fund’s Board of Directors. Fees waived and expenses paid under this agreement (and a previous limitation of 0.75%) are subject to reimbursement to T. Rowe Price Associates, Inc., by the fund whenever the class’ expense ratio is below 0.75%. However, no reimbursement will be made more than three years from the date such amounts were initially waived or reimbursed. The fund may only make repayments to T. Rowe Price Associates, Inc., if such repayment does not cause the class’ expense ratio (after the repayment is taken into account) to exceed the lesser of: (1) the expense limitation in place at the time such amounts were waived; or (2) the class’ current expense limitation.

[1] Effective July 1, 2018, the MSCI All Country World Index Net replaced the MSCI All Country World Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional International Funds, Inc.

Prospectus Date

rr_ProspectusDate

Mar. 01, 2019

T. Rowe Price Institutional Global Focused Growth Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. ROWE PRICE<br/><br/>Institutional Global Focused Growth Equity Fund<br/><br/>SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks long-term growth of capital through investments primarily in the common stocks of established companies throughout the world, including the U.S.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Fees and Expenses of the Fund<br/><br/> <b>Shareholder fees (fees paid directly from your investment)</b>

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

<b>Annual fund operating expenses<br/> (expenses that you pay each year as a<br/> percentage of the value of your investment)</b>

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

February 28, 2021

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 111.5% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

111.50%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. The example also assumes that an expense limitation arrangement currently in place is not renewed; therefore, the figures have been adjusted to reflect fee waivers or expense reimbursements only in the periods for which the expense limitation arrangement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance<br/><br/> Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The fund seeks to be broadly diversified by investing in a variety of industries in developed and, to a lesser extent, emerging markets. The fund normally invests in at least five countries, one of which is the U.S. Under normal conditions, at least 80% of the fund’s net assets (including any borrowings for investment purposes) will be invested in stocks and at least 40% of the fund’s net assets will be invested in stocks of companies outside the U.S. (at least 30% if foreign market conditions are not favorable). While the fund has flexibility to purchase stocks of companies of any size, investments will typically focus on large- and mid-cap growth stocks. The fund may at times invest significantly in certain sectors, such as the information technology sector.

While the adviser invests with an awareness of the global economic backdrop and the adviser’s outlook for certain industries, sectors, and individual countries, the adviser’s decision-making process focuses on bottom-up stock selection. Country allocation is driven largely by stock selection, though the adviser may limit investments in markets or industries that appear to have poor overall prospects.

Security selection reflects a growth style. The adviser relies on a global team of investment analysts dedicated to in-depth fundamental research in an effort to identify companies capable of achieving and sustaining above-average, long-term earnings growth. The adviser seeks to purchase stocks of companies at reasonable prices in relation to present or anticipated earnings, cash flow, or book value.

In selecting investments, the adviser generally favors companies with one or more of the following characteristics:

• leading or improving market position;

• attractive business niche;

• attractive or improving franchise or industry position;

• seasoned management;

• stable or improving earnings and/or cash flow; and

• sound or improving balance sheet.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall asset allocation investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes and restrictions on gaining access to the fund’s investments.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Market capitalization risks The fund’s focus on large companies subjects the fund to the risks that larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and that they may be less capable of responding quickly to competitive challenges and industry changes. Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies typically have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the information technology sector. Companies in the information technology sector can be adversely affected by, among other things, intense competition, earnings disappointments, and rapid obsolescence of products and services due to technological innovations or changing consumer preferences.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund.<br/><br/>The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.<br/><br/>The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

<b>troweprice.com</b>

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

<b>INSTITUTIONAL GLOBAL FOCUSED GROWTH EQUITY FUND</b><br/>Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	22.81%	Worst Quarter	9/30/11	-19.37%

Performance Table Heading

rr_PerformanceTableHeading

<b>Average Annual Total Returns<br/><br/>Periods ended<br/>December 31, 2018</b>

Performance Table Market Index Changed

rr_PerformanceTableMarketIndexChanged

Effective July 1, 2018, the MSCI All Country World Index Net replaced the MSCI All Country World Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional Global Focused Growth Equity Fund | T. Rowe Price Institutional Global Focused Growth Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)

rr_RedemptionFeeOverRedemption

2.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.65%

Other expenses

rr_OtherExpensesOverAssets

0.52%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.17%

Fee waiver/expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

(0.42%)

^[2]

Total annual fund operating expenses after fee waiver/expense reimbursement

rr_NetExpensesOverAssets

0.75%

^[2]

1 year

rr_ExpenseExampleYear01

$ 77

3 years

rr_ExpenseExampleYear03

286

5 years

rr_ExpenseExampleYear05

560

10 years

rr_ExpenseExampleYear10

$ 1,343

2009

rr_AnnualReturn2009

43.57%

2010

rr_AnnualReturn2010

12.44%

2011

rr_AnnualReturn2011

(11.31%)

2012

rr_AnnualReturn2012

16.17%

2013

rr_AnnualReturn2013

32.30%

2014

rr_AnnualReturn2014

6.32%

2015

rr_AnnualReturn2015

7.16%

2016

rr_AnnualReturn2016

6.04%

2017

rr_AnnualReturn2017

33.26%

2018

rr_AnnualReturn2018

(4.19%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

<b>Best Quarter</b>

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

22.81%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

<b>Worst Quarter</b>

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(19.37%)

1 Year

rr_AverageAnnualReturnYear01

(4.19%)

5 Years

rr_AverageAnnualReturnYear05

9.06%

10 Years

rr_AverageAnnualReturnYear10

13.00%

Inception date

rr_AverageAnnualReturnInceptionDate

Jun. 30, 2006

T. Rowe Price Institutional Global Focused Growth Equity Fund | Returns after taxes on distributions | T. Rowe Price Institutional Global Focused Growth Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(7.74%)

5 Years

rr_AverageAnnualReturnYear05

5.34%

10 Years

rr_AverageAnnualReturnYear10

10.99%

Inception date

rr_AverageAnnualReturnInceptionDate

Jun. 30, 2006

T. Rowe Price Institutional Global Focused Growth Equity Fund | Returns after taxes on distributions and sale of fund shares | T. Rowe Price Institutional Global Focused Growth Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(0.71%)

5 Years

rr_AverageAnnualReturnYear05

6.43%

10 Years

rr_AverageAnnualReturnYear10

10.51%

Inception date

rr_AverageAnnualReturnInceptionDate

Jun. 30, 2006

T. Rowe Price Institutional Global Focused Growth Equity Fund | MSCI All Country World Index Net (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(9.41%)

^[3]

5 Years

rr_AverageAnnualReturnYear05

4.26%

^[3]

10 Years

rr_AverageAnnualReturnYear10

9.46%

^[3]

T. Rowe Price Institutional Global Focused Growth Equity Fund | MSCI All Country World Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(8.93%)

5 Years

rr_AverageAnnualReturnYear05

4.82%

10 Years

rr_AverageAnnualReturnYear10

10.05%

T. Rowe Price Institutional Global Focused Growth Equity Fund | Lipper Global Multi-Cap Growth Funds Average

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(8.58%)

5 Years

rr_AverageAnnualReturnYear05

4.63%

10 Years

rr_AverageAnnualReturnYear10

10.26%

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[2] T. Rowe Price Associates, Inc., has agreed (through February 28, 2021) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the class’ ratio of expenses to average daily net assets to exceed 0.75%. The agreement may be terminated at any time beyond February 28, 2021, with approval by the fund’s Board of Directors. Fees waived and expenses paid under this agreement (and a previous limitation of 0.75%) are subject to reimbursement to T. Rowe Price Associates, Inc., by the fund whenever the class’ expense ratio is below 0.75%. However, no reimbursement will be made more than three years from the date such amounts were initially waived or reimbursed. The fund may only make repayments to T. Rowe Price Associates, Inc., if such repayment does not cause the class’ expense ratio (after the repayment is taken into account) to exceed the lesser of: (1) the expense limitation in place at the time such amounts were waived; or (2) the class’ current expense limitation.

[3] Effective July 1, 2018, the MSCI All Country World Index Net replaced the MSCI All Country World Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

XML

T. Rowe Price Institutional Global Growth Equity Fund

T. ROWE PRICE<br/><br/>Institutional Global Growth Equity Fund<br/><br/>SUMMARY

Investment Objective

The fund seeks long-term growth of capital through investments primarily in the common stocks of large-cap companies throughout the world, including the U.S.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund<br/><br/><b>Shareholder fees (fees paid directly from your investment)</b>

Shareholder Fees	T. Rowe Price Institutional Global Growth Equity Fund T. Rowe Price Institutional Global Growth Equity Fund
Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)	2.00%	[1]

<b>Annual fund operating expenses<br/>(expenses that you pay each year as a<br/>percentage of the value of your investment)</b>

Annual Fund Operating Expenses	T. Rowe Price Institutional Global Growth Equity Fund T. Rowe Price Institutional Global Growth Equity Fund
Management fees	0.65%
Other expenses	0.08%
Total annual fund operating expenses	0.73%	[1]

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional Global Growth Equity Fund | T. Rowe Price Institutional Global Growth Equity Fund | USD ($)	75	233	406	906

Portfolio Turnover

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 76.2% of the average value of its portfolio.

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

The fund normally invests at least 80% of its net assets (including any borrowings for investment purposes) in stocks of large-cap companies. Under normal conditions, the fund will invest in at least five countries, one of which will be the U.S., and at least 40% of its net assets will be invested in stocks of large-cap companies outside the U.S., including companies in emerging markets (at least 30% if foreign market conditions are not favorable).

The fund defines a large-cap company as one whose market capitalization (number of shares outstanding multiplied by share price) falls within or above the applicable range for companies included in the MSCI All Country World Large Cap Index. The fund’s and MSCI Inc.’s definition of a large-cap company depends on whether the company is located in a developed market or an emerging market. As of December 31, 2018, the Index’s market capitalization range for large-cap companies in developed markets was approximately $5 billion to $785 billion, and the market capitalization range for large-cap companies in emerging markets was approximately $970 million to $382 billion. The fund also relies on MSCI Inc. to classify a particular country as developed or emerging. The market capitalization of the companies in the fund’s portfolio and the Index changes over time; the fund will not automatically sell or cease to purchase additional stock of a company it already owns just because the company’s market capitalization falls below the range of the Index.

While the adviser invests with an awareness of the global economic backdrop and the adviser’s outlook for certain industries, sectors, and individual countries, the adviser’s decision-making process focuses on bottom-up stock selection. Country allocation is driven largely by stock selection, though the adviser may limit investments in markets or industries that appear to have poor overall prospects.

Security selection reflects a growth style. The adviser relies on a global team of investment analysts dedicated to in-depth fundamental research in an effort to identify companies capable of achieving and sustaining above-average, long-term earnings growth. The adviser seeks to purchase stocks of companies at reasonable prices in relation to present or anticipated earnings, cash flow, or book value.

In selecting investments, the adviser generally favors companies with one or more of the following characteristics:

• leading or improving market position;

• attractive business niche;

• attractive or improving franchise or industry position;

• seasoned management;

• stable or improving earnings and/or cash flow; and

• sound or improving balance sheet.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes and restrictions on gaining access to the fund’s investments.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Market capitalization risks Although stocks issued by larger companies tend to have less overall volatility than stocks issued by smaller companies, larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods. In addition, larger companies may be less capable of responding quickly to competitive challenges and industry changes, and may suffer sharper price declines as a result of earnings disappointments.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

<b>INSTITUTIONAL GLOBAL GROWTH EQUITY FUND</b><br/>Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	27.42%	Worst Quarter	9/30/11	-19.59%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

<b>Average Annual Total Returns </b><br/><br/><b>Periods ended </b><br/><b>December 31, 2018</b>

Average Annual Total Returns - T. Rowe Price Institutional Global Growth Equity Fund		1 Year	5 Years	10 Years	Inception date
T. Rowe Price Institutional Global Growth Equity Fund		(6.80%)	7.30%	12.41%	Oct. 27, 2008
T. Rowe Price Institutional Global Growth Equity Fund | Returns after taxes on distributions		(8.98%)	5.75%	10.89%	Oct. 27, 2008
T. Rowe Price Institutional Global Growth Equity Fund | Returns after taxes on distributions and sale of fund shares		(3.23%)	5.29%	9.81%	Oct. 27, 2008
MSCI All Country World Index Net (reflects no deduction for fees or expenses)	[1]	(9.41%)	4.26%	9.46%
MSCI All Country World Index (reflects no deduction for fees, expenses, or taxes)		(8.93%)	4.82%	10.05%
Lipper Global Multi-Cap Growth Funds Average		(8.58%)	4.63%	10.26%

Updated performance information is available through troweprice.com.

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[1] Restated to reflect current fees.

[1] Effective July 1, 2018, the MSCI All Country World Index Net replaced the MSCI All Country World Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional International Funds, Inc.

Prospectus Date

rr_ProspectusDate

Mar. 01, 2019

T. Rowe Price Institutional Global Growth Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. ROWE PRICE<br/><br/>Institutional Global Growth Equity Fund<br/><br/>SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks long-term growth of capital through investments primarily in the common stocks of large-cap companies throughout the world, including the U.S.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Fees and Expenses of the Fund<br/><br/><b>Shareholder fees (fees paid directly from your investment)</b>

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

<b>Annual fund operating expenses<br/>(expenses that you pay each year as a<br/>percentage of the value of your investment)</b>

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 76.2% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

76.20%

Expenses Restated to Reflect Current [Text]

rr_ExpensesRestatedToReflectCurrent

Restated to reflect current fees.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The fund normally invests at least 80% of its net assets (including any borrowings for investment purposes) in stocks of large-cap companies. Under normal conditions, the fund will invest in at least five countries, one of which will be the U.S., and at least 40% of its net assets will be invested in stocks of large-cap companies outside the U.S., including companies in emerging markets (at least 30% if foreign market conditions are not favorable).

The fund defines a large-cap company as one whose market capitalization (number of shares outstanding multiplied by share price) falls within or above the applicable range for companies included in the MSCI All Country World Large Cap Index. The fund’s and MSCI Inc.’s definition of a large-cap company depends on whether the company is located in a developed market or an emerging market. As of December 31, 2018, the Index’s market capitalization range for large-cap companies in developed markets was approximately $5 billion to $785 billion, and the market capitalization range for large-cap companies in emerging markets was approximately $970 million to $382 billion. The fund also relies on MSCI Inc. to classify a particular country as developed or emerging. The market capitalization of the companies in the fund’s portfolio and the Index changes over time; the fund will not automatically sell or cease to purchase additional stock of a company it already owns just because the company’s market capitalization falls below the range of the Index.

While the adviser invests with an awareness of the global economic backdrop and the adviser’s outlook for certain industries, sectors, and individual countries, the adviser’s decision-making process focuses on bottom-up stock selection. Country allocation is driven largely by stock selection, though the adviser may limit investments in markets or industries that appear to have poor overall prospects.

Security selection reflects a growth style. The adviser relies on a global team of investment analysts dedicated to in-depth fundamental research in an effort to identify companies capable of achieving and sustaining above-average, long-term earnings growth. The adviser seeks to purchase stocks of companies at reasonable prices in relation to present or anticipated earnings, cash flow, or book value.

In selecting investments, the adviser generally favors companies with one or more of the following characteristics:

• leading or improving market position;

• attractive business niche;

• attractive or improving franchise or industry position;

• seasoned management;

• stable or improving earnings and/or cash flow; and

• sound or improving balance sheet.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes and restrictions on gaining access to the fund’s investments.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Market capitalization risks Although stocks issued by larger companies tend to have less overall volatility than stocks issued by smaller companies, larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods. In addition, larger companies may be less capable of responding quickly to competitive challenges and industry changes, and may suffer sharper price declines as a result of earnings disappointments.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund.<br/><br/>The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.<br/><br/>The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

<b>troweprice.com</b>

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

<b>INSTITUTIONAL GLOBAL GROWTH EQUITY FUND</b><br/>Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	27.42%	Worst Quarter	9/30/11	-19.59%

Performance Table Heading

rr_PerformanceTableHeading

<b>Average Annual Total Returns </b><br/><br/><b>Periods ended </b><br/><b>December 31, 2018</b>

Performance Table Market Index Changed

rr_PerformanceTableMarketIndexChanged

Effective July 1, 2018, the MSCI All Country World Index Net replaced the MSCI All Country World Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional Global Growth Equity Fund | T. Rowe Price Institutional Global Growth Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)

rr_RedemptionFeeOverRedemption

2.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.65%

Other expenses

rr_OtherExpensesOverAssets

0.08%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.73%

^[2]

1 year

rr_ExpenseExampleYear01

$ 75

3 years

rr_ExpenseExampleYear03

233

5 years

rr_ExpenseExampleYear05

406

10 years

rr_ExpenseExampleYear10

$ 906

2009

rr_AnnualReturn2009

50.15%

2010

rr_AnnualReturn2010

14.52%

2011

rr_AnnualReturn2011

(10.28%)

2012

rr_AnnualReturn2012

21.99%

2013

rr_AnnualReturn2013

20.33%

2014

rr_AnnualReturn2014

8.56%

2015

rr_AnnualReturn2015

1.44%

2016

rr_AnnualReturn2016

2.93%

2017

rr_AnnualReturn2017

34.62%

2018

rr_AnnualReturn2018

(6.80%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

<b>Best Quarter</b>

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

27.42%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

<b>Worst Quarter</b>

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(19.59%)

1 Year

rr_AverageAnnualReturnYear01

(6.80%)

5 Years

rr_AverageAnnualReturnYear05

7.30%

10 Years

rr_AverageAnnualReturnYear10

12.41%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 27, 2008

T. Rowe Price Institutional Global Growth Equity Fund | Returns after taxes on distributions | T. Rowe Price Institutional Global Growth Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(8.98%)

5 Years

rr_AverageAnnualReturnYear05

5.75%

10 Years

rr_AverageAnnualReturnYear10

10.89%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 27, 2008

T. Rowe Price Institutional Global Growth Equity Fund | Returns after taxes on distributions and sale of fund shares | T. Rowe Price Institutional Global Growth Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(3.23%)

5 Years

rr_AverageAnnualReturnYear05

5.29%

10 Years

rr_AverageAnnualReturnYear10

9.81%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 27, 2008

T. Rowe Price Institutional Global Growth Equity Fund | MSCI All Country World Index Net (reflects no deduction for fees or expenses)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(9.41%)

^[3]

5 Years

rr_AverageAnnualReturnYear05

4.26%

^[3]

10 Years

rr_AverageAnnualReturnYear10

9.46%

^[3]

T. Rowe Price Institutional Global Growth Equity Fund | MSCI All Country World Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(8.93%)

5 Years

rr_AverageAnnualReturnYear05

4.82%

10 Years

rr_AverageAnnualReturnYear10

10.05%

T. Rowe Price Institutional Global Growth Equity Fund | Lipper Global Multi-Cap Growth Funds Average

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(8.58%)

5 Years

rr_AverageAnnualReturnYear05

4.63%

10 Years

rr_AverageAnnualReturnYear10

10.26%

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[2] Restated to reflect current fees.

[3] Effective July 1, 2018, the MSCI All Country World Index Net replaced the MSCI All Country World Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

XML

T. Rowe Price Institutional Global Value Equity Fund

T. ROWE PRICE<br/><br/>Institutional Global Value Equity Fund<br/><br/>SUMMARY

Investment Objective

The fund seeks long-term capital appreciation.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund<br/><br/><b>Shareholder fees (fees paid directly from your investment)</b>

Shareholder Fees	T. Rowe Price Institutional Global Value Equity Fund T. Rowe Price Institutional Global Value Equity Fund
Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)	2.00%	[1]

<b>Annual fund operating expenses<br/>(expenses that you pay each year as a<br/>percentage of the value of your investment)</b>

Annual Fund Operating Expenses	T. Rowe Price Institutional Global Value Equity Fund T. Rowe Price Institutional Global Value Equity Fund
Management fees	0.65%
Other expenses	2.25%
Total annual fund operating expenses	2.90%
Fee waiver/expense reimbursement	(2.15%)	[1]
Total annual fund operating expenses after fee waiver/expense reimbursement	0.75%	[1]

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. The example also assumes that an expense limitation arrangement currently in place is not renewed; therefore, the figures have been adjusted to reflect fee waivers or expense reimbursements only in the periods for which the expense limitation arrangement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional Global Value Equity Fund | T. Rowe Price Institutional Global Value Equity Fund | USD ($)	77	694	1,338	3,069

Portfolio Turnover

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 100.4% of the average value of its portfolio.

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

The fund normally invests at least 80% of its net assets (including any borrowings for investment purposes) in equity securities issued by companies throughout the world. The percentage of assets allocated to investments outside the U.S. will vary according to the portfolio manager’s outlook. However, under normal conditions, at least 40% of the fund’s net assets will be invested in companies outside the U.S. (and at least 30% of its net assets will be invested in companies outside the U.S. if foreign market conditions are not favorable). The fund invests in companies across a broad range of industries in the U.S. and developed markets and, to a lesser extent, emerging markets. Although the fund may invest in companies of any size, investments will generally be made in stocks of large- and mid-cap companies.

While the adviser invests with an awareness of the global economic landscape and the outlook for certain industries and countries, stock selection is driven mainly by fundamental research that seeks to identify companies that are undervalued but have the potential for improving earnings over time. The fund’s value approach to investing relies on a global research team that searches for companies that appear to be undervalued by various measures and may be temporarily out of favor but have good prospects for capital appreciation or dividend growth. The fund may at times invest significantly in certain sectors, such as the financials sector.

In selecting investments, the adviser generally favors companies with one or more of the following characteristics:

• low valuation on various earnings, book value, sales, and cash flow metrics, in absolute terms and/or relative to the company’s peers or its own historical norm;

• low valuation relative to a company’s fundamentals;

• companies that may benefit from restructuring activity or other turnaround opportunities;

• a sound balance sheet and other positive financial characteristics; and

• above-average dividend yield and/or the potential to grow dividends.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes and restrictions on gaining access to the fund’s investments for foreign investors.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s value approach to investing could cause it to underperform when compared to other stock funds that employ a different investment style. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Market capitalization risks The fund’s focus on large companies subjects the fund to the risks that larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and that they may be less capable of responding quickly to competitive challenges and industry changes. Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies typically have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the financials sector. Companies in the financials sector may be adversely impacted by, among other things, regulatory changes, economic conditions, interest rates, credit rating downgrades, and decreased liquidity in credit markets.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

<b>INSTITUTIONAL GLOBAL VALUE EQUITY FUND</B><br/>Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	9/30/13	9.48%	Worst Quarter	12/31/18	-13.41%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

<b>Average Annual Total Returns</b><br/><br/><b>Periods ended </b><br/><b> December 31, 2018</b>

Average Annual Total Returns - T. Rowe Price Institutional Global Value Equity Fund		1 Year	5 Years	Since inception		Inception date
T. Rowe Price Institutional Global Value Equity Fund		(13.67%)	3.76%	9.27%		Jul. 26, 2012
T. Rowe Price Institutional Global Value Equity Fund | Returns after taxes on distributions		(15.36%)	1.62%	7.04%		Jul. 26, 2012
T. Rowe Price Institutional Global Value Equity Fund | Returns after taxes on distributions and sales of fund returns		(6.85%)	2.70%	7.06%		Jul. 26, 2012
MSCI World Index Net (reflects no deduction for fees or expenses)	[1]	(8.71%)	4.56%	9.00%
MSCI World Index (reflects no deduction for fees, expenses, or taxes)		(8.20%)	5.14%	9.61%	[2]	Jul. 26, 2012
Lipper Global Multi-Cap Value Funds Average		(12.77%)	2.24%	6.33%	[3]	Jul. 31, 2012

Updated performance information is available through troweprice.com.

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[1] T. Rowe Price Associates, Inc., has agreed (through February 29, 2020) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the fund’s ratio of expenses to average daily net assets to exceed 0.75%. The agreement may be terminated at any time beyond February 29, 2020, with approval by the fund’s Board of Directors. Fees waived and expenses paid under this agreement (and a previous limitation of 0.75%) are subject to reimbursement to T. Rowe Price Associates, Inc., by the fund whenever the fund’s expense ratio is below 0.75%. However, no reimbursement will be made more than three years from the date such amounts were initially waived or reimbursed. The fund may only make repayments to T. Rowe Price Associates, Inc., if such repayment does not cause the fund’s expense ratio (after the repayment is taken into account) to exceed the lesser of: (1) the expense limitation in place at the time such amounts were waived; or (2) the fund’s current expense limitation.

[1] Effective July 1, 2018, the MSCI World Index Net replaced the MSCI World Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

[2] Return since 7/26/12.

[3] Return since 7/31/12.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional International Funds, Inc.

Prospectus Date

rr_ProspectusDate

Mar. 01, 2019

T. Rowe Price Institutional Global Value Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. ROWE PRICE<br/><br/>Institutional Global Value Equity Fund<br/><br/>SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks long-term capital appreciation.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Fees and Expenses of the Fund<br/><br/><b>Shareholder fees (fees paid directly from your investment)</b>

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

<b>Annual fund operating expenses<br/>(expenses that you pay each year as a<br/>percentage of the value of your investment)</b>

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

February 29, 2020

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 100.4% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

100.40%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. The example also assumes that an expense limitation arrangement currently in place is not renewed; therefore, the figures have been adjusted to reflect fee waivers or expense reimbursements only in the periods for which the expense limitation arrangement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The fund normally invests at least 80% of its net assets (including any borrowings for investment purposes) in equity securities issued by companies throughout the world. The percentage of assets allocated to investments outside the U.S. will vary according to the portfolio manager’s outlook. However, under normal conditions, at least 40% of the fund’s net assets will be invested in companies outside the U.S. (and at least 30% of its net assets will be invested in companies outside the U.S. if foreign market conditions are not favorable). The fund invests in companies across a broad range of industries in the U.S. and developed markets and, to a lesser extent, emerging markets. Although the fund may invest in companies of any size, investments will generally be made in stocks of large- and mid-cap companies.

While the adviser invests with an awareness of the global economic landscape and the outlook for certain industries and countries, stock selection is driven mainly by fundamental research that seeks to identify companies that are undervalued but have the potential for improving earnings over time. The fund’s value approach to investing relies on a global research team that searches for companies that appear to be undervalued by various measures and may be temporarily out of favor but have good prospects for capital appreciation or dividend growth. The fund may at times invest significantly in certain sectors, such as the financials sector.

In selecting investments, the adviser generally favors companies with one or more of the following characteristics:

• low valuation on various earnings, book value, sales, and cash flow metrics, in absolute terms and/or relative to the company’s peers or its own historical norm;

• low valuation relative to a company’s fundamentals;

• companies that may benefit from restructuring activity or other turnaround opportunities;

• a sound balance sheet and other positive financial characteristics; and

• above-average dividend yield and/or the potential to grow dividends.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes and restrictions on gaining access to the fund’s investments for foreign investors.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s value approach to investing could cause it to underperform when compared to other stock funds that employ a different investment style. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Market capitalization risks The fund’s focus on large companies subjects the fund to the risks that larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and that they may be less capable of responding quickly to competitive challenges and industry changes. Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies typically have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the financials sector. Companies in the financials sector may be adversely impacted by, among other things, regulatory changes, economic conditions, interest rates, credit rating downgrades, and decreased liquidity in credit markets.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund. <br/><br/>The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.<br/><br/>The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

<b>troweprice.com</b>

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

<b>INSTITUTIONAL GLOBAL VALUE EQUITY FUND</B><br/>Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	9/30/13	9.48%	Worst Quarter	12/31/18	-13.41%

Performance Table Heading

rr_PerformanceTableHeading

<b>Average Annual Total Returns</b><br/><br/><b>Periods ended </b><br/><b> December 31, 2018</b>

Performance Table Market Index Changed

rr_PerformanceTableMarketIndexChanged

Effective July 1, 2018, the MSCI World Index Net replaced the MSCI World Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional Global Value Equity Fund | T. Rowe Price Institutional Global Value Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)

rr_RedemptionFeeOverRedemption

2.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.65%

Other expenses

rr_OtherExpensesOverAssets

2.25%

Total annual fund operating expenses

rr_ExpensesOverAssets

2.90%

Fee waiver/expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

(2.15%)

^[2]

Total annual fund operating expenses after fee waiver/expense reimbursement

rr_NetExpensesOverAssets

0.75%

^[2]

1 year

rr_ExpenseExampleYear01

$ 77

3 years

rr_ExpenseExampleYear03

694

5 years

rr_ExpenseExampleYear05

1,338

10 years

rr_ExpenseExampleYear10

$ 3,069

2013

rr_AnnualReturn2013

30.92%

2014

rr_AnnualReturn2014

7.70%

2015

rr_AnnualReturn2015

(1.18%)

2016

rr_AnnualReturn2016

9.46%

2017

rr_AnnualReturn2017

19.59%

2018

rr_AnnualReturn2018

(13.67%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

<b>Best Quarter</b>

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2013

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

9.48%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

<b>Worst Quarter</b>

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2018

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(13.41%)

1 Year

rr_AverageAnnualReturnYear01

(13.67%)

5 Years

rr_AverageAnnualReturnYear05

3.76%

Since inception

rr_AverageAnnualReturnSinceInception

9.27%

Inception date

rr_AverageAnnualReturnInceptionDate

Jul. 26, 2012

T. Rowe Price Institutional Global Value Equity Fund | Returns after taxes on distributions | T. Rowe Price Institutional Global Value Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(15.36%)

5 Years

rr_AverageAnnualReturnYear05

1.62%

Since inception

rr_AverageAnnualReturnSinceInception

7.04%

Inception date

rr_AverageAnnualReturnInceptionDate

Jul. 26, 2012

T. Rowe Price Institutional Global Value Equity Fund | Returns after taxes on distributions and sales of fund returns | T. Rowe Price Institutional Global Value Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(6.85%)

5 Years

rr_AverageAnnualReturnYear05

2.70%

Since inception

rr_AverageAnnualReturnSinceInception

7.06%

Inception date

rr_AverageAnnualReturnInceptionDate

Jul. 26, 2012

T. Rowe Price Institutional Global Value Equity Fund | MSCI World Index Net (reflects no deduction for fees or expenses)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(8.71%)

^[3]

5 Years

rr_AverageAnnualReturnYear05

4.56%

^[3]

Since inception

rr_AverageAnnualReturnSinceInception

9.00%

^[3]

T. Rowe Price Institutional Global Value Equity Fund | MSCI World Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(8.20%)

5 Years

rr_AverageAnnualReturnYear05

5.14%

Since inception

rr_AverageAnnualReturnSinceInception

9.61%

^[4]

Inception date

rr_AverageAnnualReturnInceptionDate

Jul. 26, 2012

T. Rowe Price Institutional Global Value Equity Fund | Lipper Global Multi-Cap Value Funds Average

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(12.77%)

5 Years

rr_AverageAnnualReturnYear05

2.24%

Since inception

rr_AverageAnnualReturnSinceInception

6.33%

^[5]

Inception date

rr_AverageAnnualReturnInceptionDate

Jul. 31, 2012

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[2] T. Rowe Price Associates, Inc., has agreed (through February 29, 2020) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the fund’s ratio of expenses to average daily net assets to exceed 0.75%. The agreement may be terminated at any time beyond February 29, 2020, with approval by the fund’s Board of Directors. Fees waived and expenses paid under this agreement (and a previous limitation of 0.75%) are subject to reimbursement to T. Rowe Price Associates, Inc., by the fund whenever the fund’s expense ratio is below 0.75%. However, no reimbursement will be made more than three years from the date such amounts were initially waived or reimbursed. The fund may only make repayments to T. Rowe Price Associates, Inc., if such repayment does not cause the fund’s expense ratio (after the repayment is taken into account) to exceed the lesser of: (1) the expense limitation in place at the time such amounts were waived; or (2) the fund’s current expense limitation.

[3] Effective July 1, 2018, the MSCI World Index Net replaced the MSCI World Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

[4] Return since 7/26/12.

[5] Return since 7/31/12.

XML

T. Rowe Price Institutional International Concentrated Equity Fund

T. ROWE PRICE<br/><br/>Institutional International Disciplined Equity Fund<br/><br/>(formerly T. Rowe Price Institutional International Concentrated Equity Fund)<br/><br/>SUMMARY

Investment Objective

The fund seeks long-term growth of capital through investments in stocks of non-U.S. companies.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund<br/><br/><b>Shareholder fees (fees paid directly from your investment)</b>

Shareholder Fees	T. Rowe Price Institutional International Concentrated Equity Fund T. Rowe Price Institutional International Concentrated Equity Fund
Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)	2.00%	[1]

<b>Annual fund operating expenses<br/>(expenses that you pay each year as a<br/>percentage of the value of your investment)</b>

Annual Fund Operating Expenses	T. Rowe Price Institutional International Concentrated Equity Fund T. Rowe Price Institutional International Concentrated Equity Fund
Management fees	0.65%
Other expenses	0.09%
Total annual fund operating expenses	0.74%
Fee waiver/expense reimbursement	0.01%	[1]
Total annual fund operating expenses after fee waiver/expense reimbursement	0.75%	[1]

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. The example also assumes that an expense limitation arrangement currently in place is not renewed; therefore, the figures have been adjusted to reflect fee waivers or expense reimbursements only in the periods for which the expense limitation arrangement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional International Concentrated Equity Fund | T. Rowe Price Institutional International Concentrated Equity Fund | USD ($)	77	239	413	920

Portfolio Turnover

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 147.0% of the average value of its portfolio.

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

The fund expects to primarily invest in stocks of companies located outside the U.S. Under normal conditions, the fund will invest at least 80% of its net assets (including any borrowings for investment purposes) in stocks of non-U.S. companies and no more than 15% of its net assets will be invested in stocks of companies in emerging markets. For purposes of determining whether the fund invests at least 80% of its net assets in non-U.S. stocks, the fund relies on the country assigned to a security by MSCI Inc. or another unaffiliated data provider. Because the fund focuses on developed markets outside the U.S., it typically has significant exposure to companies in Europe.

The fund is “nondiversified,” meaning it may invest a greater portion of its assets in a single company and own more of the company’s voting securities than is permissible for a “diversified” fund.

While the adviser invests with an awareness of the global economic backdrop and the adviser’s outlook for certain industries, sectors, and individual countries, the adviser’s decision-making process focuses on bottom-up stock selection. Country allocation is driven largely by stock selection, though the adviser may limit investments in markets or industries that appear to have poor overall prospects.

The fund may purchase the stocks of companies of any size, but typically focuses on larger companies, and does not emphasize either a growth or value bias in selecting investments. The adviser generally selects securities for the fund that the adviser believes have the most favorable combination of company fundamentals, earnings potential, and relative valuation.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes and restrictions on gaining access to the fund’s investments.

Geographic concentration risks To the extent the fund concentrates its investments in a particular geographic region, the fund’s performance is closely tied to the social, political, and economic conditions within that region. Political developments and changes in regulatory, tax, or economic policy in particular countries within the region could significantly affect the markets in those countries as well as the entire region. As a result, the fund is likely to be more volatile than more geographically diverse international funds.

The European financial markets have been experiencing increased volatility due to concerns over rising government debt levels of several European countries, and these events may continue to significantly affect all of Europe. European economies could be significantly affected by, among other things, rising unemployment, the imposition or unexpected elimination of fiscal and monetary controls by member countries of the European Economic and Monetary Union, uncertainty surrounding the euro, the success of governmental actions to reduce budget deficits, and a disorderly exit by the United Kingdom from the European Union.

Nondiversification risks As a nondiversified fund, the fund has the ability to invest a larger percentage of its assets in the securities of a smaller number of issuers than a diversified fund. As a result, poor performance by a single issuer could adversely affect fund performance more than if the fund were invested in a larger number of issuers. The fund’s share price can be expected to fluctuate more than that of a comparable diversified fund.

Market capitalization risks The fund’s focus on large companies subjects the fund to the risks that larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and that they may be less capable of responding quickly to competitive challenges and industry changes. Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies typically have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The performance for the periods shown reflects the performance of the fund while it was named the T. Rowe Price Institutional International Concentrated Equity Fund. Effective March 1, 2019, the T. Rowe Price Institutional International Concentrated Equity Fund was renamed the T. Rowe Price Institutional International Disciplined Equity Fund.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

<b>INSTITUTIONAL INTERNATIONAL DISCIPLINED EQUITY FUND </b><br/>Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	3/31/12	11.51%	Worst Quarter	9/30/11	-15.73%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

<b>Average Annual Total Returns</b><br/><br/><b>Periods ended </b><br/><b>December 31, 2018</b>

Average Annual Total Returns - T. Rowe Price Institutional International Concentrated Equity Fund		1 Year	5 Years	Since inception		Inception date
T. Rowe Price Institutional International Concentrated Equity Fund		(10.32%)	1.91%	6.76%		Jul. 27, 2010
T. Rowe Price Institutional International Concentrated Equity Fund | Returns after taxes on distributions		(14.18%)	0.30%	4.81%		Jul. 27, 2010
T. Rowe Price Institutional International Concentrated Equity Fund | Returns after taxes on distributions and sale of fund shares		(4.08%)	1.25%	4.96%		Jul. 27, 2010
MSCI EAFE Index Net (reflects no deduction for fees or expenses)	[1]	(13.79%)	0.53%	4.71%	[2]	Jul. 27, 2010
MSCI EAFE Index (reflects no deduction for fees, expenses, or taxes)		(13.36%)	1.00%	5.18%	[2]	Jul. 27, 2010
Lipper International Multi-Cap Core Funds Average		(15.08%)	0.12%	4.21%	[3]	Jul. 31, 2010

Updated performance information is available through troweprice.com.

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[1] T. Rowe Price Associates, Inc., has agreed (through February 28, 2021) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the fund’s ratio of expenses to average daily net assets to exceed 0.75%. The agreement may be terminated at any time beyond February 28, 2021, with approval by the fund’s Board of Directors. Fees waived and expenses paid under this agreement (and a previous limitation of 0.75%) are subject to reimbursement to T. Rowe Price Associates, Inc., by the fund whenever the fund’s expense ratio is below 0.75%. However, no reimbursement will be made more than three years from the date such amounts were initially waived or reimbursed. The fund may only make repayments to T. Rowe Price Associates, Inc., if such repayment does not cause the fund’s expense ratio (after the repayment is taken into account) to exceed the lesser of: (1) the expense limitation in place at the time such amounts were waived; or (2) the fund’s current expense limitation.

[1] Effective July 1, 2018, the MSCI EAFE Index Net replaced the MSCI EAFE Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

[2] Return since 7/27/10.

[3] Return since 7/31/10.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional International Funds, Inc.

Prospectus Date

rr_ProspectusDate

Mar. 01, 2019

T. Rowe Price Institutional International Concentrated Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. ROWE PRICE<br/><br/>Institutional International Disciplined Equity Fund<br/><br/>(formerly T. Rowe Price Institutional International Concentrated Equity Fund)<br/><br/>SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks long-term growth of capital through investments in stocks of non-U.S. companies.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Fees and Expenses of the Fund<br/><br/><b>Shareholder fees (fees paid directly from your investment)</b>

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

<b>Annual fund operating expenses<br/>(expenses that you pay each year as a<br/>percentage of the value of your investment)</b>

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

February 28, 2021

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 147.0% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

147.00%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. The example also assumes that an expense limitation arrangement currently in place is not renewed; therefore, the figures have been adjusted to reflect fee waivers or expense reimbursements only in the periods for which the expense limitation arrangement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The fund expects to primarily invest in stocks of companies located outside the U.S. Under normal conditions, the fund will invest at least 80% of its net assets (including any borrowings for investment purposes) in stocks of non-U.S. companies and no more than 15% of its net assets will be invested in stocks of companies in emerging markets. For purposes of determining whether the fund invests at least 80% of its net assets in non-U.S. stocks, the fund relies on the country assigned to a security by MSCI Inc. or another unaffiliated data provider. Because the fund focuses on developed markets outside the U.S., it typically has significant exposure to companies in Europe.

The fund is “nondiversified,” meaning it may invest a greater portion of its assets in a single company and own more of the company’s voting securities than is permissible for a “diversified” fund.

While the adviser invests with an awareness of the global economic backdrop and the adviser’s outlook for certain industries, sectors, and individual countries, the adviser’s decision-making process focuses on bottom-up stock selection. Country allocation is driven largely by stock selection, though the adviser may limit investments in markets or industries that appear to have poor overall prospects.

The fund may purchase the stocks of companies of any size, but typically focuses on larger companies, and does not emphasize either a growth or value bias in selecting investments. The adviser generally selects securities for the fund that the adviser believes have the most favorable combination of company fundamentals, earnings potential, and relative valuation.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes and restrictions on gaining access to the fund’s investments.

Geographic concentration risks To the extent the fund concentrates its investments in a particular geographic region, the fund’s performance is closely tied to the social, political, and economic conditions within that region. Political developments and changes in regulatory, tax, or economic policy in particular countries within the region could significantly affect the markets in those countries as well as the entire region. As a result, the fund is likely to be more volatile than more geographically diverse international funds.

The European financial markets have been experiencing increased volatility due to concerns over rising government debt levels of several European countries, and these events may continue to significantly affect all of Europe. European economies could be significantly affected by, among other things, rising unemployment, the imposition or unexpected elimination of fiscal and monetary controls by member countries of the European Economic and Monetary Union, uncertainty surrounding the euro, the success of governmental actions to reduce budget deficits, and a disorderly exit by the United Kingdom from the European Union.

Nondiversification risks As a nondiversified fund, the fund has the ability to invest a larger percentage of its assets in the securities of a smaller number of issuers than a diversified fund. As a result, poor performance by a single issuer could adversely affect fund performance more than if the fund were invested in a larger number of issuers. The fund’s share price can be expected to fluctuate more than that of a comparable diversified fund.

Market capitalization risks The fund’s focus on large companies subjects the fund to the risks that larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and that they may be less capable of responding quickly to competitive challenges and industry changes. Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies typically have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Risk Nondiversified Status [Text]

rr_RiskNondiversifiedStatus

Nondiversification risks As a nondiversified fund, the fund has the ability to invest a larger percentage of its assets in the securities of a smaller number of issuers than a diversified fund. As a result, poor performance by a single issuer could adversely affect fund performance more than if the fund were invested in a larger number of issuers. The fund’s share price can be expected to fluctuate more than that of a comparable diversified fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The performance for the periods shown reflects the performance of the fund while it was named the T. Rowe Price Institutional International Concentrated Equity Fund. Effective March 1, 2019, the T. Rowe Price Institutional International Concentrated Equity Fund was renamed the T. Rowe Price Institutional International Disciplined Equity Fund.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund.<br/><br/>The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.<br/><br/>The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

<b>troweprice.com</b>

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

<b>INSTITUTIONAL INTERNATIONAL DISCIPLINED EQUITY FUND </b><br/>Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	3/31/12	11.51%	Worst Quarter	9/30/11	-15.73%

Performance Table Heading

rr_PerformanceTableHeading

<b>Average Annual Total Returns</b><br/><br/><b>Periods ended </b><br/><b>December 31, 2018</b>

Performance Table Market Index Changed

rr_PerformanceTableMarketIndexChanged

Effective July 1, 2018, the MSCI EAFE Index Net replaced the MSCI EAFE Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional International Concentrated Equity Fund | T. Rowe Price Institutional International Concentrated Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)

rr_RedemptionFeeOverRedemption

2.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.65%

Other expenses

rr_OtherExpensesOverAssets

0.09%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.74%

Fee waiver/expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

0.01%

^[2]

Total annual fund operating expenses after fee waiver/expense reimbursement

rr_NetExpensesOverAssets

0.75%

^[2]

1 year

rr_ExpenseExampleYear01

$ 77

3 years

rr_ExpenseExampleYear03

239

5 years

rr_ExpenseExampleYear05

413

10 years

rr_ExpenseExampleYear10

$ 920

2011

rr_AnnualReturn2011

(6.58%)

2012

rr_AnnualReturn2012

21.91%

2013

rr_AnnualReturn2013

24.75%

2014

rr_AnnualReturn2014

(4.36%)

2015

rr_AnnualReturn2015

0.46%

2016

rr_AnnualReturn2016

4.84%

2017

rr_AnnualReturn2017

21.69%

2018

rr_AnnualReturn2018

(10.32%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

<b>Best Quarter</b>

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Mar. 31, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

11.51%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

<b>Worst Quarter</b>

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(15.73%)

1 Year

rr_AverageAnnualReturnYear01

(10.32%)

5 Years

rr_AverageAnnualReturnYear05

1.91%

Since inception

rr_AverageAnnualReturnSinceInception

6.76%

Inception date

rr_AverageAnnualReturnInceptionDate

Jul. 27, 2010

T. Rowe Price Institutional International Concentrated Equity Fund | Returns after taxes on distributions | T. Rowe Price Institutional International Concentrated Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(14.18%)

5 Years

rr_AverageAnnualReturnYear05

0.30%

Since inception

rr_AverageAnnualReturnSinceInception

4.81%

Inception date

rr_AverageAnnualReturnInceptionDate

Jul. 27, 2010

T. Rowe Price Institutional International Concentrated Equity Fund | Returns after taxes on distributions and sale of fund shares | T. Rowe Price Institutional International Concentrated Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(4.08%)

5 Years

rr_AverageAnnualReturnYear05

1.25%

Since inception

rr_AverageAnnualReturnSinceInception

4.96%

Inception date

rr_AverageAnnualReturnInceptionDate

Jul. 27, 2010

T. Rowe Price Institutional International Concentrated Equity Fund | MSCI EAFE Index Net (reflects no deduction for fees or expenses)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(13.79%)

^[3]

5 Years

rr_AverageAnnualReturnYear05

0.53%

^[3]

Since inception

rr_AverageAnnualReturnSinceInception

4.71%

^[3],[4]

Inception date

rr_AverageAnnualReturnInceptionDate

Jul. 27, 2010

^[3]

T. Rowe Price Institutional International Concentrated Equity Fund | MSCI EAFE Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(13.36%)

5 Years

rr_AverageAnnualReturnYear05

1.00%

Since inception

rr_AverageAnnualReturnSinceInception

5.18%

^[4]

Inception date

rr_AverageAnnualReturnInceptionDate

Jul. 27, 2010

T. Rowe Price Institutional International Concentrated Equity Fund | Lipper International Multi-Cap Core Funds Average

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(15.08%)

5 Years

rr_AverageAnnualReturnYear05

0.12%

Since inception

rr_AverageAnnualReturnSinceInception

4.21%

^[5]

Inception date

rr_AverageAnnualReturnInceptionDate

Jul. 31, 2010

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[2] T. Rowe Price Associates, Inc., has agreed (through February 28, 2021) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the fund’s ratio of expenses to average daily net assets to exceed 0.75%. The agreement may be terminated at any time beyond February 28, 2021, with approval by the fund’s Board of Directors. Fees waived and expenses paid under this agreement (and a previous limitation of 0.75%) are subject to reimbursement to T. Rowe Price Associates, Inc., by the fund whenever the fund’s expense ratio is below 0.75%. However, no reimbursement will be made more than three years from the date such amounts were initially waived or reimbursed. The fund may only make repayments to T. Rowe Price Associates, Inc., if such repayment does not cause the fund’s expense ratio (after the repayment is taken into account) to exceed the lesser of: (1) the expense limitation in place at the time such amounts were waived; or (2) the fund’s current expense limitation.

[3] Effective July 1, 2018, the MSCI EAFE Index Net replaced the MSCI EAFE Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

[4] Return since 7/27/10.

[5] Return since 7/31/10.

XML

T. Rowe Price Institutional International Core Equity Fund

T. ROWE PRICE<br/><br/>Institutional International Core Equity Fund<br/><br/>SUMMARY

Investment Objective

The fund seeks long-term growth of capital through investments in the common stocks of non-U.S. companies.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund<br/><br/><b>Shareholder fees (fees paid directly from your investment)</b>

Shareholder Fees	T. Rowe Price Institutional International Core Equity Fund T. Rowe Price Institutional International Core Equity Fund
Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)	2.00%	[1]

<b>Annual fund operating expenses<br/>(expenses that you pay each year as a<br/>percentage of the value of your investment)</b>

Annual Fund Operating Expenses	T. Rowe Price Institutional International Core Equity Fund T. Rowe Price Institutional International Core Equity Fund
Management fees	0.65%
Other expenses	0.21%
Total annual fund operating expenses	0.86%
Fee waiver/expense reimbursement	(0.11%)	[1]
Total annual fund operating expenses after fee waiver/expense reimbursement	0.75%	[1]

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. The example also assumes that an expense limitation arrangement currently in place is not renewed; therefore, the figures have been adjusted to reflect fee waivers or expense reimbursements only in the periods for which the expense limitation arrangement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional International Core Equity Fund | T. Rowe Price Institutional International Core Equity Fund | USD ($)	77	252	455	1,040

Portfolio Turnover

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 32.3% of the average value of its portfolio.

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

The fund expects to invest significantly outside the U.S. and to diversify broadly among developed markets and, to a lesser extent, emerging market countries throughout the world. The fund normally invests at least 80% of its net assets (including any borrowings for investment purposes) in non-U.S. stocks and at least 65% of its net assets in stocks of large-cap companies. For purposes of determining whether the fund invests at least 80% of its net assets in non-U.S. stocks, the fund relies on the country assigned to a security by MSCI Inc. or another unaffiliated data provider. The fund may at times invest significantly in certain sectors, such as the financials sector.

The fund takes a core approach to investing, which provides some exposure to both growth and value styles of investing. The adviser relies on a global research team to search for particularly promising stocks. The adviser will select securities that the adviser believes have the most favorable combination of company fundamentals and valuation.

In selecting investments, the adviser generally favors companies with one or more of the following characteristics:

• attractive business niche with potential for earnings growth;

• attractive valuation relative to the company’s peers or its own historical norm;

• barriers to entry in its business;

• seasoned management;

• healthy balance sheet; and

• potential to grow dividends or conduct share repurchases.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes and restrictions on gaining access to the fund’s investments for foreign investors.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. Because the fund may hold stocks with either growth or value characteristics, it could underperform other stock funds that take a strictly growth or value approach to investing when one style is currently in favor. Growth stocks tend to be more volatile than the overall stock market and can have sharp price declines as a result of earnings disappointments. Value stocks carry the risk that the market will not recognize their intrinsic value or that they are actually appropriately priced at a low level.

Market capitalization risks Although stocks issued by larger companies tend to have less overall volatility than stocks issued by smaller companies, larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods. In addition, larger companies may be less capable of responding quickly to competitive challenges and industry changes, and may suffer sharper price declines as a result of earnings disappointments.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the financials sector. Companies in the financials sector may be adversely impacted by, among other things, regulatory changes, economic conditions, interest rates, credit rating downgrades, and decreased liquidity in credit markets.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

<b>INSTITUTIONAL INTERNATIONAL CORE EQUITY FUND</b><br/>Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	3/31/12	12.17%	Worst Quarter	9/30/11	-20.68%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

<b>Average Annual Total Returns</b><br/><br/><b>Periods ended</b><br/><b>December 31, 2018</b>

Average Annual Total Returns - T. Rowe Price Institutional International Core Equity Fund		1 Year	5 Years	Since inception		Inception date
T. Rowe Price Institutional International Core Equity Fund		(15.33%)	0.62%	4.26%		Oct. 27, 2010
T. Rowe Price Institutional International Core Equity Fund | Returns after taxes on distributions		(16.10%)	0.13%	3.85%		Oct. 27, 2010
T. Rowe Price Institutional International Core Equity Fund | Returns after taxes on distributions and sale of fund shares		(7.19%)	0.79%	3.66%		Oct. 27, 2010
MSCI EAFE Index Net (reflects no deduction for fees or expenses)	[1]	(13.79%)	0.53%	3.76%	[2]	Oct. 27, 2010
MSCI EAFE Index (reflects no deduction for fees, expenses, or taxes)		(13.36%)	1.00%	4.23%	[2]	Oct. 27, 2010
Lipper International Large-Cap Core Funds Average		(15.46%)	(0.50%)	2.60%	[3]	Oct. 31, 2010

Updated performance information is available through troweprice.com.

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[1] T. Rowe Price Associates, Inc., has agreed (through February 28, 2021) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the ratio of expenses to average daily net assets to exceed 0.75%. The agreement may be terminated at any time beyond February 28, 2021, with approval by the fund’s Board of Directors. Fees waived and expenses paid under this agreement (and a previous limitation of 0.75%) are subject to reimbursement to T. Rowe Price Associates, Inc., by the fund whenever the expense ratio is below 0.75%. However, no reimbursement will be made more than three years from the date such amounts were initially waived or reimbursed. The fund may only make repayments to T. Rowe Price Associates, Inc., if such repayment does not cause the expense ratio (after the repayment is taken into account) to exceed the lesser of: (1) the expense limitation in place at the time such amounts were waived; or (2) the current expense limitation.

[1] Effective July 1, 2018, the MSCI EAFE Index Net replaced the MSCI EAFE Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

[2] Return since 10/27/10.

[3] Return since 10/31/10.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional International Funds, Inc.

Prospectus Date

rr_ProspectusDate

Mar. 01, 2019

T. Rowe Price Institutional International Core Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. ROWE PRICE<br/><br/>Institutional International Core Equity Fund<br/><br/>SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks long-term growth of capital through investments in the common stocks of non-U.S. companies.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Fees and Expenses of the Fund<br/><br/><b>Shareholder fees (fees paid directly from your investment)</b>

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

<b>Annual fund operating expenses<br/>(expenses that you pay each year as a<br/>percentage of the value of your investment)</b>

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

February 28, 2021

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 32.3% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

32.30%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. The example also assumes that an expense limitation arrangement currently in place is not renewed; therefore, the figures have been adjusted to reflect fee waivers or expense reimbursements only in the periods for which the expense limitation arrangement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The fund expects to invest significantly outside the U.S. and to diversify broadly among developed markets and, to a lesser extent, emerging market countries throughout the world. The fund normally invests at least 80% of its net assets (including any borrowings for investment purposes) in non-U.S. stocks and at least 65% of its net assets in stocks of large-cap companies. For purposes of determining whether the fund invests at least 80% of its net assets in non-U.S. stocks, the fund relies on the country assigned to a security by MSCI Inc. or another unaffiliated data provider. The fund may at times invest significantly in certain sectors, such as the financials sector.

The fund takes a core approach to investing, which provides some exposure to both growth and value styles of investing. The adviser relies on a global research team to search for particularly promising stocks. The adviser will select securities that the adviser believes have the most favorable combination of company fundamentals and valuation.

In selecting investments, the adviser generally favors companies with one or more of the following characteristics:

• attractive business niche with potential for earnings growth;

• attractive valuation relative to the company’s peers or its own historical norm;

• barriers to entry in its business;

• seasoned management;

• healthy balance sheet; and

• potential to grow dividends or conduct share repurchases.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes and restrictions on gaining access to the fund’s investments for foreign investors.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. Because the fund may hold stocks with either growth or value characteristics, it could underperform other stock funds that take a strictly growth or value approach to investing when one style is currently in favor. Growth stocks tend to be more volatile than the overall stock market and can have sharp price declines as a result of earnings disappointments. Value stocks carry the risk that the market will not recognize their intrinsic value or that they are actually appropriately priced at a low level.

Market capitalization risks Although stocks issued by larger companies tend to have less overall volatility than stocks issued by smaller companies, larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods. In addition, larger companies may be less capable of responding quickly to competitive challenges and industry changes, and may suffer sharper price declines as a result of earnings disappointments.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the financials sector. Companies in the financials sector may be adversely impacted by, among other things, regulatory changes, economic conditions, interest rates, credit rating downgrades, and decreased liquidity in credit markets.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund. <br/><br/>The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.<br/><br/>The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

<b>troweprice.com</b>

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

<b>INSTITUTIONAL INTERNATIONAL CORE EQUITY FUND</b><br/>Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	3/31/12	12.17%	Worst Quarter	9/30/11	-20.68%

Performance Table Heading

rr_PerformanceTableHeading

<b>Average Annual Total Returns</b><br/><br/><b>Periods ended</b><br/><b>December 31, 2018</b>

Performance Table Market Index Changed

rr_PerformanceTableMarketIndexChanged

Effective July 1, 2018, the MSCI EAFE Index Net replaced the MSCI EAFE Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional International Core Equity Fund | T. Rowe Price Institutional International Core Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)

rr_RedemptionFeeOverRedemption

2.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.65%

Other expenses

rr_OtherExpensesOverAssets

0.21%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.86%

Fee waiver/expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

(0.11%)

^[2]

Total annual fund operating expenses after fee waiver/expense reimbursement

rr_NetExpensesOverAssets

0.75%

^[2]

1 year

rr_ExpenseExampleYear01

$ 77

3 years

rr_ExpenseExampleYear03

252

5 years

rr_ExpenseExampleYear05

455

10 years

rr_ExpenseExampleYear10

$ 1,040

2011

rr_AnnualReturn2011

(10.51%)

2012

rr_AnnualReturn2012

19.25%

2013

rr_AnnualReturn2013

22.25%

2014

rr_AnnualReturn2014

(4.88%)

2015

rr_AnnualReturn2015

(2.75%)

2016

rr_AnnualReturn2016

2.91%

2017

rr_AnnualReturn2017

27.97%

2018

rr_AnnualReturn2018

(15.33%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

<b>Best Quarter</b>

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Mar. 31, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

12.17%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

<b>Worst Quarter</b>

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(20.68%)

1 Year

rr_AverageAnnualReturnYear01

(15.33%)

5 Years

rr_AverageAnnualReturnYear05

0.62%

Since inception

rr_AverageAnnualReturnSinceInception

4.26%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 27, 2010

T. Rowe Price Institutional International Core Equity Fund | Returns after taxes on distributions | T. Rowe Price Institutional International Core Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(16.10%)

5 Years

rr_AverageAnnualReturnYear05

0.13%

Since inception

rr_AverageAnnualReturnSinceInception

3.85%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 27, 2010

T. Rowe Price Institutional International Core Equity Fund | Returns after taxes on distributions and sale of fund shares | T. Rowe Price Institutional International Core Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(7.19%)

5 Years

rr_AverageAnnualReturnYear05

0.79%

Since inception

rr_AverageAnnualReturnSinceInception

3.66%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 27, 2010

T. Rowe Price Institutional International Core Equity Fund | MSCI EAFE Index Net (reflects no deduction for fees or expenses)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(13.79%)

^[3]

5 Years

rr_AverageAnnualReturnYear05

0.53%

^[3]

Since inception

rr_AverageAnnualReturnSinceInception

3.76%

^[3],[4]

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 27, 2010

^[3]

T. Rowe Price Institutional International Core Equity Fund | MSCI EAFE Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(13.36%)

5 Years

rr_AverageAnnualReturnYear05

1.00%

Since inception

rr_AverageAnnualReturnSinceInception

4.23%

^[4]

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 27, 2010

T. Rowe Price Institutional International Core Equity Fund | Lipper International Large-Cap Core Funds Average

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(15.46%)

5 Years

rr_AverageAnnualReturnYear05

(0.50%)

Since inception

rr_AverageAnnualReturnSinceInception

2.60%

^[5]

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 31, 2010

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[2] T. Rowe Price Associates, Inc., has agreed (through February 28, 2021) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the ratio of expenses to average daily net assets to exceed 0.75%. The agreement may be terminated at any time beyond February 28, 2021, with approval by the fund’s Board of Directors. Fees waived and expenses paid under this agreement (and a previous limitation of 0.75%) are subject to reimbursement to T. Rowe Price Associates, Inc., by the fund whenever the expense ratio is below 0.75%. However, no reimbursement will be made more than three years from the date such amounts were initially waived or reimbursed. The fund may only make repayments to T. Rowe Price Associates, Inc., if such repayment does not cause the expense ratio (after the repayment is taken into account) to exceed the lesser of: (1) the expense limitation in place at the time such amounts were waived; or (2) the current expense limitation.

[3] Effective July 1, 2018, the MSCI EAFE Index Net replaced the MSCI EAFE Index as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

[4] Return since 10/27/10.

[5] Return since 10/31/10.

XML

T. Rowe Price Institutional International Growth Equity Fund

T. ROWE PRICE<br/><br/> Institutional International Growth Equity Fund <br/><br/>SUMMARY

Investment Objective

The fund seeks long-term growth of capital through investments primarily in the common stocks of established, non-U.S. companies.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund<br/><br/><b>Shareholder fees (fees paid directly from your investment)</b>

Shareholder Fees	T. Rowe Price Institutional International Growth Equity Fund T. Rowe Price Institutional International Growth Equity Fund
Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)	2.00%	[1]

<b>Annual fund operating expenses<br/>(expenses that you pay each year as a<br/>percentage of the value of your investment)</b>

Annual Fund Operating Expenses	T. Rowe Price Institutional International Growth Equity Fund T. Rowe Price Institutional International Growth Equity Fund
Management fees	0.70%
Other expenses	0.46%
Total annual fund operating expenses	1.16%
Fee waiver/expense reimbursement	(0.41%)	[1]
Total annual fund operating expenses after fee waiver/expense reimbursement	0.75%	[1]

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. The example also assumes that an expense limitation arrangement currently in place is not renewed; therefore, the figures have been adjusted to reflect fee waivers or expense reimbursements only in the periods for which the expense limitation arrangement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional International Growth Equity Fund | T. Rowe Price Institutional International Growth Equity Fund | USD ($)	77	328	599	1,372

Portfolio Turnover

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 39.1% of the average value of its portfolio.

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

The fund expects to primarily invest in stocks outside the U.S. and to diversify broadly among developed and emerging countries throughout the world. The fund may purchase the stocks of companies of any size, but its focus will typically be on large companies and, to a lesser extent, medium-sized companies. Normally, at least 80% of the fund’s net assets (including any borrowings for investment purposes) will be invested in stocks.

While the adviser invests with an awareness of the global economic backdrop and the adviser’s outlook for certain industries, sectors, and individual countries, the adviser’s decision-making process focuses on bottom-up stock selection. Country allocation is driven largely by stock selection, though the adviser may limit investments in markets or industries that appear to have poor overall prospects.

Security selection reflects a growth style. The adviser relies on a global team of investment analysts dedicated to in-depth fundamental research in an effort to identify companies capable of achieving and sustaining above-average, long-term earnings growth. The adviser seeks to purchase stocks of companies at reasonable prices in relation to present or anticipated earnings, cash flow, or book value.

In selecting investments, the adviser generally favors companies with one or more of the following characteristics:

• leading or improving market position;

• attractive business niche;

• attractive or improving franchise or industry position;

• seasoned management;

• stable or improving earnings and/or cash flow; and

• sound or improving balance sheet.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S.

Emerging markets risks The risks of international investing are heightened for securities of issuers in emerging market countries. Emerging market countries tend to have economic structures that are less diverse and mature, and political systems that are less stable, than those of developed countries. In addition to all of the risks of investing in international developed markets, emerging markets are more susceptible to governmental interference, local taxes being imposed on international investments, restrictions on gaining access to the fund’s investments, and less efficient trading markets with lower overall liquidity.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Market capitalization risks The fund’s focus on large companies subjects the fund to the risks that larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and that they may be less capable of responding quickly to competitive challenges and industry changes. Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies typically have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

<b>INSTITUTIONAL INTERNATIONAL GROWTH EQUITY FUND</b><br/>Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	32.53%	Worst Quarter	9/30/11	-21.25%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

<b>Average Annual Total Returns <br/><br/>Periods ended<br/>December 31, 2018 </b>

Average Annual Total Returns - T. Rowe Price Institutional International Growth Equity Fund		1 Year	5 Years	10 Years	Inception date
T. Rowe Price Institutional International Growth Equity Fund		(13.96%)	2.15%	8.63%	Sep. 07, 1989
T. Rowe Price Institutional International Growth Equity Fund | Returns after taxes on distributions		(15.59%)	1.22%	8.05%	Sep. 07, 1989
T. Rowe Price Institutional International Growth Equity Fund | Returns after taxes on distributions and sale of fund shares		(7.07%)	1.70%	7.18%	Sep. 07, 1989
MSCI All Country World Index ex USA Net (reflects no deduction for fees or expenses)	[1]	(14.20%)	0.68%	6.57%
MSCI All Country World Index ex USA (reflects no deduction for fees, expenses, or taxes)		(13.78%)	1.14%	7.06%
Lipper International Multi-Cap Growth Funds Average		(15.36%)	0.58%	6.77%

Updated performance information is available through troweprice.com.

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[1] T. Rowe Price Associates, Inc., has agreed (through February 29, 2020) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the fund's ratio of expenses to average daily net assets to exceed 0.75%. The agreement may be terminated at any time beyond February 29, 2020, with approval by the fund’s Board of Directors. Fees waived and expenses paid under this agreement (and a previous limitation of 0.75%) are subject to reimbursement to T. Rowe Price Associates, Inc., by the fund whenever the fund's expense ratio is below 0.75%. However, no reimbursement will be made more than three years from the date such amounts were initially waived or reimbursed. The fund may only make repayments to T. Rowe Price Associates, Inc., if such repayment does not cause the fund's expense ratio (after the repayment is taken into account) to exceed the lesser of: (1) the expense limitation in place at the time such amounts were waived; or (2) the fund's current expense limitation.

[1] Effective July 1, 2018, the MSCI All Country World Index ex USA Net replaced the MSCI All Country World Index ex USA as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional International Funds, Inc.

Prospectus Date

rr_ProspectusDate

Mar. 01, 2019

T. Rowe Price Institutional International Growth Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. ROWE PRICE<br/><br/> Institutional International Growth Equity Fund <br/><br/>SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks long-term growth of capital through investments primarily in the common stocks of established, non-U.S. companies.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Fees and Expenses of the Fund<br/><br/><b>Shareholder fees (fees paid directly from your investment)</b>

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

<b>Annual fund operating expenses<br/>(expenses that you pay each year as a<br/>percentage of the value of your investment)</b>

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

February 29, 2020

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 39.1% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

39.10%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. The example also assumes that an expense limitation arrangement currently in place is not renewed; therefore, the figures have been adjusted to reflect fee waivers or expense reimbursements only in the periods for which the expense limitation arrangement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The fund expects to primarily invest in stocks outside the U.S. and to diversify broadly among developed and emerging countries throughout the world. The fund may purchase the stocks of companies of any size, but its focus will typically be on large companies and, to a lesser extent, medium-sized companies. Normally, at least 80% of the fund’s net assets (including any borrowings for investment purposes) will be invested in stocks.

While the adviser invests with an awareness of the global economic backdrop and the adviser’s outlook for certain industries, sectors, and individual countries, the adviser’s decision-making process focuses on bottom-up stock selection. Country allocation is driven largely by stock selection, though the adviser may limit investments in markets or industries that appear to have poor overall prospects.

Security selection reflects a growth style. The adviser relies on a global team of investment analysts dedicated to in-depth fundamental research in an effort to identify companies capable of achieving and sustaining above-average, long-term earnings growth. The adviser seeks to purchase stocks of companies at reasonable prices in relation to present or anticipated earnings, cash flow, or book value.

In selecting investments, the adviser generally favors companies with one or more of the following characteristics:

• leading or improving market position;

• attractive business niche;

• attractive or improving franchise or industry position;

• seasoned management;

• stable or improving earnings and/or cash flow; and

• sound or improving balance sheet.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

International investing risks Investing in the securities of non-U.S. issuers involves special risks not typically associated with investing in U.S. issuers. International securities tend to be more volatile and have lower overall liquidity than investments in U.S. securities and may lose value because of adverse local, political, social, or economic developments overseas, or due to changes in the exchange rates between foreign currencies and the U.S. dollar. In addition, international investments are subject to settlement practices and regulatory and financial reporting standards that differ from those of the U.S.

Emerging markets risks The risks of international investing are heightened for securities of issuers in emerging market countries. Emerging market countries tend to have economic structures that are less diverse and mature, and political systems that are less stable, than those of developed countries. In addition to all of the risks of investing in international developed markets, emerging markets are more susceptible to governmental interference, local taxes being imposed on international investments, restrictions on gaining access to the fund’s investments, and less efficient trading markets with lower overall liquidity.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Market capitalization risks The fund’s focus on large companies subjects the fund to the risks that larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and that they may be less capable of responding quickly to competitive challenges and industry changes. Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies typically have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund. <br/><br/>The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.<br/><br/>The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

<b>troweprice.com</b>

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

<b>INSTITUTIONAL INTERNATIONAL GROWTH EQUITY FUND</b><br/>Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	32.53%	Worst Quarter	9/30/11	-21.25%

Performance Table Heading

rr_PerformanceTableHeading

<b>Average Annual Total Returns <br/><br/>Periods ended<br/>December 31, 2018 </b>

Performance Table Market Index Changed

rr_PerformanceTableMarketIndexChanged

Effective July 1, 2018, the MSCI All Country World Index ex USA Net replaced the MSCI All Country World Index ex USA as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional International Growth Equity Fund | T. Rowe Price Institutional International Growth Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)

rr_RedemptionFeeOverRedemption

2.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.70%

Other expenses

rr_OtherExpensesOverAssets

0.46%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.16%

Fee waiver/expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

(0.41%)

^[2]

Total annual fund operating expenses after fee waiver/expense reimbursement

rr_NetExpensesOverAssets

0.75%

^[2]

1 year

rr_ExpenseExampleYear01

$ 77

3 years

rr_ExpenseExampleYear03

328

5 years

rr_ExpenseExampleYear05

599

10 years

rr_ExpenseExampleYear10

$ 1,372

2009

rr_AnnualReturn2009

51.17%

2010

rr_AnnualReturn2010

14.57%

2011

rr_AnnualReturn2011

(12.42%)

2012

rr_AnnualReturn2012

18.64%

2013

rr_AnnualReturn2013

14.34%

2014

rr_AnnualReturn2014

(0.92%)

2015

rr_AnnualReturn2015

(0.71%)

2016

rr_AnnualReturn2016

2.38%

2017

rr_AnnualReturn2017

28.35%

2018

rr_AnnualReturn2018

(13.96%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

<b>Best Quarter</b>

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

32.53%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

<b>Worst Quarter</b>

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(21.25%)

1 Year

rr_AverageAnnualReturnYear01

(13.96%)

5 Years

rr_AverageAnnualReturnYear05

2.15%

10 Years

rr_AverageAnnualReturnYear10

8.63%

Inception date

rr_AverageAnnualReturnInceptionDate

Sep. 07, 1989

T. Rowe Price Institutional International Growth Equity Fund | Returns after taxes on distributions | T. Rowe Price Institutional International Growth Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(15.59%)

5 Years

rr_AverageAnnualReturnYear05

1.22%

10 Years

rr_AverageAnnualReturnYear10

8.05%

Inception date

rr_AverageAnnualReturnInceptionDate

Sep. 07, 1989

T. Rowe Price Institutional International Growth Equity Fund | Returns after taxes on distributions and sale of fund shares | T. Rowe Price Institutional International Growth Equity Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(7.07%)

5 Years

rr_AverageAnnualReturnYear05

1.70%

10 Years

rr_AverageAnnualReturnYear10

7.18%

Inception date

rr_AverageAnnualReturnInceptionDate

Sep. 07, 1989

T. Rowe Price Institutional International Growth Equity Fund | MSCI All Country World Index ex USA Net (reflects no deduction for fees or expenses)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(14.20%)

^[3]

5 Years

rr_AverageAnnualReturnYear05

0.68%

^[3]

10 Years

rr_AverageAnnualReturnYear10

6.57%

^[3]

T. Rowe Price Institutional International Growth Equity Fund | MSCI All Country World Index ex USA (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(13.78%)

5 Years

rr_AverageAnnualReturnYear05

1.14%

10 Years

rr_AverageAnnualReturnYear10

7.06%

T. Rowe Price Institutional International Growth Equity Fund | Lipper International Multi-Cap Growth Funds Average

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(15.36%)

5 Years

rr_AverageAnnualReturnYear05

0.58%

10 Years

rr_AverageAnnualReturnYear10

6.77%

[1] Effective April 1, 2019, the fund will no longer assess a redemption fee on any redemption from the fund (or exchange out of the fund), regardless of how long the shares were held.

[2] T. Rowe Price Associates, Inc., has agreed (through February 29, 2020) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the fund's ratio of expenses to average daily net assets to exceed 0.75%. The agreement may be terminated at any time beyond February 29, 2020, with approval by the fund’s Board of Directors. Fees waived and expenses paid under this agreement (and a previous limitation of 0.75%) are subject to reimbursement to T. Rowe Price Associates, Inc., by the fund whenever the fund's expense ratio is below 0.75%. However, no reimbursement will be made more than three years from the date such amounts were initially waived or reimbursed. The fund may only make repayments to T. Rowe Price Associates, Inc., if such repayment does not cause the fund's expense ratio (after the repayment is taken into account) to exceed the lesser of: (1) the expense limitation in place at the time such amounts were waived; or (2) the fund's current expense limitation.

[3] Effective July 1, 2018, the MSCI All Country World Index ex USA Net replaced the MSCI All Country World Index ex USA as the fund’s primary benchmark. The new index assumes the reinvestment of dividends after the deduction of withholding taxes applicable to the country where the dividend is paid; as such, the returns of the new benchmark are more representative of the returns experienced by investors in foreign issuers.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	T. Rowe Price Institutional International Funds, Inc.
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
Document Creation Date	dei_DocumentCreationDate	Feb. 27, 2019