Investments and Fair Value Measurements (Gains (Losses) on Investments) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010
Available-for-sale:
Available-for-sale securities, amortized cost basis	$ 90,560	$ 124,557
Available-for-sale securities, unrealized gain	1,269	2,517
Available-for-sale securities, unrealized loss	(368)	(1,288)
Available-for-sale securities, current	91,461	125,786
Held-to-maturity:
Held-to-maturity securities, total amortized cost	31,214	26,357
Held-to-maturity securities, unrealized gain	0	0
Held-to-maturity securities, unrealized loss	0	0
Held-to-maturity securities, current	31,214	26,357
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Available-for-sale securities, realized gains	5,550	1,671	761
Available-for-sale securities, realized losses	(1,343)	(1,133)	(501)
Available-for-sale securities, realized gains, net	4,207	538	260
US Treasury and Government [Member]
Available-for-sale:
Available-for-sale securities, amortized cost basis	19,693	40,669
Available-for-sale securities, unrealized gain	8	29
Available-for-sale securities, unrealized loss	(3)	(608)
Available-for-sale securities, fair value disclosure	19,698	40,090
Corporate Bonds [Member]
Available-for-sale:
Available-for-sale securities, amortized cost basis	49,913	49,339
Available-for-sale securities, unrealized gain	22	36
Available-for-sale securities, unrealized loss	(124)	(292)
Available-for-sale securities, fair value disclosure	49,811	49,083
Foreign obligations [Member]
Available-for-sale:
Available-for-sale securities, amortized cost basis	505	2,437
Available-for-sale securities, unrealized gain	0	1
Available-for-sale securities, unrealized loss	(2)	(19)
Available-for-sale securities, fair value disclosure	503	2,419
Commercial paper [Member]
Available-for-sale:
Available-for-sale securities, amortized cost basis	9,482	2,000
Available-for-sale securities, unrealized gain	7	0
Available-for-sale securities, unrealized loss	0	0
Available-for-sale securities, fair value disclosure	9,489	2,000
Equity securities and exchange-traded funds [Member]
Available-for-sale:
Available-for-sale securities, amortized cost basis	8,872	19,613
Available-for-sale securities, unrealized gain	1,011	1,359
Available-for-sale securities, unrealized loss	(141)	(323)
Available-for-sale securities, fair value disclosure	9,742	20,649
Mutual funds [Member]
Available-for-sale:
Available-for-sale securities, amortized cost basis	2,095	10,499
Available-for-sale securities, unrealized gain	221	1,092
Available-for-sale securities, unrealized loss	(98)	(46)
Available-for-sale securities, fair value disclosure	$ 2,218	$ 11,545

Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax

No definition available.

Name:	morn_AvailableforsaleSecuritiesAccumulatedGrossUnrealizedGainbeforeTax
Namespace Prefix:	morn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax

+ References

No definition available.

+ Details

Name:	morn_AvailableforsaleSecuritiesAccumulatedGrossUnrealizedLossbeforeTax
Namespace Prefix:	morn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Held-to-maturity Securities, Accumulated Unrecognized Holding Gain

+ References

No definition available.

+ Details

Name:	morn_HeldtomaturitySecuritiesAccumulatedUnrecognizedHoldingGain
Namespace Prefix:	morn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Held-to-maturity Securities, Accumulated Unrecognized Holding Loss

+ References

No definition available.

+ Details

Name:	morn_HeldtomaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
Namespace Prefix:	morn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (aa)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

+ Details

Name:	us-gaap_AvailableForSaleSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.2)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesAmortizedCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in debt and equity securities categorized neither as trading securities nor held-to-maturity securities and intended be sold or mature one year or operating cycle, if longer.

+ References

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNetAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

+ References

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesGrossRealizedGains
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

+ References

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGainLossAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount before other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

+ References

No definition available.

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesAmortizedCostBeforeOtherThanTemporaryImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_HeldToMaturitySecuritiesClassifiedAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity, expected to be converted to cash, sold or exchanged within one year or the normal operating cycle.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant