Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional International Funds, Inc.

Prospectus Date

rr_ProspectusDate

Mar. 01, 2015

T. Rowe Price Institutional International Core Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

SUMMARY

T. Rowe Price Institutional International Core Equity Fund

Objective [Heading]

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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.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Fees and Expenses of the Fund

Shareholder fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual fund operating expenses
(expenses that you pay each year as a
percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

February 28, 2017

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 fund 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 18.7% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

18.70%

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. The example also assumes that your investment has a 5% return each year, the fund’s operating expenses remain the same, and the expense limitation currently in place is not renewed. 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

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The fund expects to invest substantially all of its assets outside the U.S. and to diversify broadly among developed and, to a lesser extent, emerging 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.

The fund takes a core approach to investing, which provides some exposure to both growth and value styles of investing. The fund relies on a global research team to search for particularly promising stocks throughout developed and, to a lesser extent, emerging markets. Securities will be selected that in our view have the most favorable combination of company fundamentals and valuation.

In selecting investments, the fund 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]

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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 risk The fund is subject to the risk that the investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. If the securities selected and strategies employed by the fund fail to produce the intended results, the fund could underperform other funds with similar objectives and investment strategies.

Risks of stock investing 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 prices 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 company or a particular industry.

International investing risk 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 less liquid than investments in U.S. securities and may lose value because of adverse 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.

Investment style risk Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. Because the fund holds stocks with both growth and 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.

Risk Lose Money [Text]

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

Bar Chart and Performance Table [Heading]

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Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart showing calendar year returns and the average annual total returns table indicate risk by illustrating how much returns can differ from one year to the next and how fund performance compares with that of a comparable market index. The fund’s past performance (before and after taxes) is not necessarily an indication of future performance.

The fund can also experience short-term performance swings, as shown by the best and worst calendar quarter returns during the years depicted.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The bar chart showing calendar year returns and the average annual total returns table indicate risk by illustrating how much returns can differ from one year to the next and how fund performance compares with that of a comparable market index.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

1-800-638-8790

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

troweprice.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

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

Bar Chart [Heading]

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Institutional International Core Equity Fund
Calendar Year Returns

Bar Chart Closing [Text Block]

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

Performance Table Heading

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Average Annual Total Returns

Periods ended
December 31, 2014

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 individual retirement account.

Performance Table Explanation after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

In some cases, the figure shown under “returns after taxes on distributions and sale of fund shares” may be higher than the figure shown under “returns before taxes” because the calculations assume the investor received a tax deduction for any loss incurred on the sale of shares.

Performance Table Narrative

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In addition, the average annual total returns table shows hypothetical after-tax returns to suggest 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 individual retirement account. In some cases, the figure shown under “returns after taxes on distributions and sale of fund shares” may be higher than the figure shown under “returns before taxes” because the calculations assume the investor received a tax deduction for any loss incurred on the sale of shares.

Performance Table Closing [Text Block]

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Updated performance information is available through troweprice.com or may be obtained by calling 1-800-638-8790.

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%

Management fees

rr_ManagementFeesOverAssets

0.65%

Other expenses

rr_OtherExpensesOverAssets

0.28%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.93%

Fee waiver/expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

(0.18%)

^[1]

Total annual fund operating expenses after fee waiver/expense reimbursement

rr_NetExpensesOverAssets

0.75%

^[1]

1 year

rr_ExpenseExampleYear01

77

3 years

rr_ExpenseExampleYear03

260

5 years

rr_ExpenseExampleYear05

479

10 years

rr_ExpenseExampleYear10

1,109

2011

rr_AnnualReturn2011

(10.51%)

2012

rr_AnnualReturn2012

19.25%

2013

rr_AnnualReturn2013

22.25%

2014

rr_AnnualReturn2014

(4.88%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Mar. 31, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

12.17%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst Quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(20.68%)

1 Year

rr_AverageAnnualReturnYear01

(4.88%)

Since inception

rr_AverageAnnualReturnSinceInception

6.42%

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

(5.45%)

Since inception

rr_AverageAnnualReturnSinceInception

6.08%

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

(1.98%)

Since inception

rr_AverageAnnualReturnSinceInception

5.27%

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 27, 2010

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

(4.48%)

Since inception

rr_AverageAnnualReturnSinceInception

6.00%

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

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(4.82%)

Since inception

rr_AverageAnnualReturnSinceInception

4.72%

^[2]

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 31, 2010

[1] T. Rowe Price Associates, Inc. has agreed (through February 28, 2017) to waive its fees and/or bear any expenses (excluding interest, expenses related to borrowings, taxes and brokerage, extraordinary expenses, and acquired fund fees) that would cause the fund's ratio of expenses to average daily net assets to exceed 0.75%. Termination of the agreement would require approval by the fund's Board of Directors. Fees waived and expenses paid under this agreement 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 after the waiver or payment, or if it would result in the expense ratio exceeding 0.75% (excluding interest, expenses related to borrowings, taxes and brokerage, extraordinary expenses, and acquired fund fees).

[2] Returns as of 10/31/10.