MSCI (MSCI) 10-Q 1 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Oct. 28, 2013
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'MSCI	'
Entity Registrant Name	'MSCI INC.	'
Entity Central Index Key	'0001408198	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	118,403,925

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Financial Condition (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
ASSETS	'	'
Cash and cash equivalents	$283,750	$183,309
Short-term investments	'	70,898
Accounts receivable (net of allowances of $978 and $964 at September 30, 2013 and December 31, 2012, respectively)	179,920	153,557
Deferred taxes	50,386	49,552
Prepaid taxes	47,377	32,431
Prepaid and other assets	28,662	25,088
Total current assets	590,095	514,835
Property, equipment and leasehold improvements (net of accumulated depreciation and amortization of $73,856 and $59,078 at September 30, 2013 and December 31, 2012, respectively)	73,809	67,419
Goodwill	1,797,223	1,783,410
Intangible assets (net of accumulated amortization of $359,513 and $316,099 at September 30, 2013 and December 31, 2012, respectively)	607,766	641,074
Other non-current assets	12,696	12,901
Total assets	3,081,589	3,019,639
LIABILITIES AND SHAREHOLDERS' EQUITY	'	'
Accounts payable	1,319	2,985
Accrued compensation and related benefits	96,030	113,359
Other accrued liabilities	46,380	42,486
Current maturities of long-term debt	54,130	43,093
Deferred revenue	334,094	308,022
Total current liabilities	531,953	509,945
Long-term debt, net of current maturities	753,285	811,623
Deferred taxes	229,877	234,245
Other non-current liabilities	44,327	38,595
Total liabilities	1,559,442	1,594,408
Commitments and Contingencies (see Note 8)	'	'
Shareholders' equity:	'	'
Preferred stock (par value $0.01; 100,000,000 shares authorized; no shares issued)	'	'
Common stock (par value $0.01; 750,000,000 common shares authorized; 125,305,504 and 124,033,980 common shares issued and 118,403,925 and 120,114,586 common shares outstanding at September 30, 2013 and December 31, 2012, respectively)	1,253	1,240
Treasury shares, at cost (6,901,579 and 3,919,394 common shares held at September 30, 2013 and December 31, 2012, respectively)	-236,136	-120,926
Additional paid in capital	1,036,732	1,000,014
Retained earnings	722,999	547,699
Accumulated other comprehensive income (loss)	-2,701	-2,796
Total shareholders' equity	1,522,147	1,425,231
Total liabilities and shareholders' equity	$3,081,589	$3,019,639

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Financial Condition (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Statement Of Financial Position [Abstract]	'	'
Accounts receivable, allowances	$978	$964
Property, equipment and leasehold improvements, accumulated depreciation and amortization	73,856	59,078
Intangible assets, accumulated amortization	$359,513	$316,099
Preferred stock, par value	$0.01	$0.01
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	750,000,000	750,000,000
Common stock, shares issued	125,305,504	124,033,980
Common stock, shares outstanding	118,403,925	120,114,586
Treasury shares	6,901,579	3,919,394

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Statement [Abstract]	'	'	'	'
Operating revenues	$258,238	$235,444	$768,045	$703,061
Operating expenses:	'	'	'	'
Cost of services	80,040	68,350	243,584	213,884
Selling, general and administrative	65,380	62,973	184,623	176,011
Restructuring	'	'	'	-51
Amortization of intangible assets	14,448	15,959	43,443	47,877
Depreciation and amortization of property, equipment and leasehold improvements	5,934	4,633	16,260	13,711
Total operating expenses	165,802	151,915	487,910	451,432
Operating income	92,436	83,529	280,135	251,629
Interest income	-265	-252	-770	-712
Interest expense	5,827	7,314	19,351	49,250
Other expense (income)	627	873	497	1,997
Other expense (income), net	6,189	7,935	19,078	50,535
Income before provision for income taxes	86,247	75,594	261,057	201,094
Provision for income taxes	30,937	27,320	85,757	71,308
Net income	$55,310	$48,274	$175,300	$129,786
Earnings per basic common share	$0.46	$0.39	$1.45	$1.06
Earnings per diluted common share	$0.46	$0.39	$1.44	$1.05
Weighted average shares outstanding used in computing earnings per share:	'	'	'	'
Basic	119,607	122,261	120,497	122,016
Diluted	120,578	123,450	121,446	123,287

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]	'	'	'	'
Net income	$55,310	$48,274	$175,300	$129,786
Other comprehensive income (loss):	'	'	'	'
Foreign currency translation adjustments	6,522	2,228	-1,252	2,166
Income tax effect	-2,519	-855	479	-867
Foreign currency translation adjustments, net	4,003	1,373	-773	1,299
Unrealized gains (losses) on cash flow hedges	197	610	1,364	1,134
Income tax effect	-77	-234	-524	-457
Unrealized gains (losses) on cash flow hedges, net	120	376	840	677
Unrealized gains (losses) on available-for-sale securities	'	10	-5	8
Income tax effect	'	-4	2	-4
Unrealized gains (losses) on available-for-sale securities, net	'	6	-3	4
Pension and other post-retirement adjustments	-68	120	47	1,033
Income tax effect	17	-56	-16	-276
Pension and other post-retirement adjustments, net	-51	64	31	757
Other comprehensive income (loss), net of tax	4,072	1,819	95	2,737
Comprehensive income	$59,382	$50,093	$175,395	$132,523

Condensed_Consolidated_Stateme4

Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities	'	'
Net income	$175,300	$129,786
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Amortization of intangible assets	43,443	47,877
Stock-based compensation expense	19,150	19,409
Depreciation and amortization of property, equipment and leasehold improvements	16,260	13,711
Amortization of debt origination fees	2,179	17,099
Deferred taxes	-2,125	-23,701
Amortization of discount on long-term debt	699	5,072
Excess tax benefits from stock-based compensation	-1,766	-1,579
Other non-cash adjustments	-748	-136
Changes in assets and liabilities, net of assets and liabilities acquired:	'	'
Accounts receivable	-26,762	56,822
Prepaid income taxes	-13,067	84
Prepaid and other assets	-3,393	436
Accounts payable	-2,017	1,448
Deferred revenue	25,454	33,301
Accrued compensation and related benefits	-16,161	-22,683
Other accrued liabilities	3,147	-4,531
Other	6,444	15,248
Net cash provided by operating activities	226,037	287,663
Cash flows from investing activities	'	'
Proceeds from redemption of short-term investments	70,900	153,032
Purchase of short-term investments	'	-106,315
Acquisitions, net of cash acquired	-23,268	'
Proceeds from the sale of capital equipment	29	'
Capitalized software development costs	-1,829	'
Capital expenditures	-20,899	-38,109
Net cash provided by investing activities	24,933	8,608
Cash flows from financing activities	'	'
Proceeds from borrowing, net of discount	'	876,087
Repayment of long-term debt	-48,000	-1,092,563
Payment of debt issuance costs	'	-3,870
Repurchase of treasury shares	-109,928	-2,924
Proceeds from exercise of stock options	9,308	10,761
Excess tax benefits from stock-based compensation	1,766	1,579
Net cash used in financing activities	-146,854	-210,930
Effect of exchange rate changes	-3,675	2,906
Net increase (decrease) in cash and cash equivalents	100,441	88,247
Cash and cash equivalents, beginning of period	183,309	252,211
Cash and cash equivalents, end of period	283,750	340,458
Supplemental disclosure of cash flow information:	'	'
Cash paid for interest	15,099	28,593
Cash paid for income taxes	99,642	92,575
Supplemental disclosure of non-cash investing activities:	'	'
Property, equipment and leasehold improvements in other accrued liabilities	$5,219	$3,463

Introduction_and_Basis_of_Pres

Introduction and Basis of Presentation	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Introduction and Basis of Presentation	'
	1. INTRODUCTION AND BASIS OF PRESENTATION
	MSCI Inc. together with its wholly-owned subsidiaries (the “Company” or “MSCI”) is a global provider of investment decision support tools, including indices, portfolio risk and performance analytics and corporate governance products and services. The Company’s flagship products are its global equity indices and environmental, social and governance (“ESG”) products marketed under the MSCI and MSCI ESG brands, its portfolio risk and performance analytics covering global equity and fixed income markets marketed under the Barra brand, its market and credit risk analytics marketed under the RiskMetrics and Barra brands, its governance research and outsourced proxy voting and reporting services, and executive compensation analytics tools marketed under the ISS brand, its valuation models and risk management software for the energy and commodities markets marketed under the FEA brand, its private real estate benchmarks marketed under the IPD brand and its products for monitoring, analyzing and reporting on institutional assets for institutional investment consultants marketed under the InvestorForce brand.
	MSCI operates as two segments: the Performance and Risk business and the Governance business. The Performance and Risk business is a global provider of investment decision support tools, including equity indices, real estate indices and benchmarks, portfolio risk and performance analytics, credit analytics and ESG products. The Governance business is a provider of corporate governance products, services and data solutions to institutional shareholders and corporations around the world. (See Note 12, “Segment Information,” for further information about MSCI’s operating segments.)
	Basis of Presentation and Use of Estimates
	These unaudited condensed consolidated financial statements include the accounts of MSCI Inc. and its subsidiaries and include all adjustments of a normal, recurring nature necessary to present fairly the financial condition as of September 30, 2013 and December 31, 2012, the results of operations and comprehensive income for the three and nine months ended September 30, 2013 and 2012 and cash flows for the nine months ended September 30, 2013 and 2012. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes included in MSCI’s Annual Report on Form 10-K for the year ended December 31, 2012. The unaudited condensed consolidated financial statement information as of December 31, 2012 has been derived from the 2012 audited consolidated financial statements. The results of operations for interim periods are not necessarily indicative of results for the entire year.
	The Company’s unaudited condensed consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). These accounting principles require the Company to make certain estimates and judgments that can affect the reported amounts of assets and liabilities as of the date of the unaudited condensed consolidated financial statements, as well as the reported amounts of revenue and expenses during the periods presented. Significant estimates and assumptions made by management include the deferral and recognition of revenue, research and development and software capitalization, the allowance for doubtful accounts, impairment of long-lived assets, accrued compensation, income taxes and other matters that affect the unaudited condensed consolidated financial statements and related disclosures. The Company believes that estimates used in the preparation of these unaudited condensed consolidated financial statements are reasonable; however, actual results could differ materially from these estimates.
	Intercompany balances and transactions are eliminated in consolidation.
	Adjustment to Revenue
	During the nine months ended September 30, 2012, as a result of a one-time adjustment, the Company recorded a $5.2 million cumulative revenue reduction to correct an immaterial error related to revenues previously reported through December 31, 2011. The effect of recording this adjustment in the nine months ended September 30, 2012 resulted in a one-time decrease to the energy and commodity analytics products revenues in the Company’s Unaudited Condensed Consolidated Statement of Income and an increase in deferred revenues in the Company’s Unaudited Condensed Consolidated Statement of Financial Condition. It was determined that under the Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification (“ASC”) Subtopic 985-605, “Software Revenue Recognition,” the Company incorrectly established vendor specific objective evidence, or VSOE, for certain energy and commodity analytics products and as a result should not have been recognizing a substantial portion of the revenue immediately upon delivery or renewal of a time-based subscription license, the terms of which are generally one year. Rather, the entire license fee should have been recognized ratably over the term of the license. As such, the Company made the cumulative adjustment effective January 1, 2012 and started recognizing revenue related to all contracts still in effect as of this date ratably over the remainder of the term. The Company began recognizing revenue ratably over the contract term for any new contracts entered into on or after January 1, 2012. Based upon an evaluation of all relevant factors, management believes the correcting adjustment did not have a material impact on the Company’s previously reported results and, accordingly, has determined that restatement of previously issued financial statements is not necessary.
	Concentrations
	Financial instruments that may potentially subject the Company to concentrations of credit risk consist principally of cash deposits and short-term investments. At September 30, 2013 and December 31, 2012, cash and cash equivalent amounts were $283.8 million and $183.3 million, respectively. The Company held no short-term investments at September 30, 2013. At December 31, 2012, the Company had invested $70.9 million in U.S. Treasury Securities with maturity dates ranging from 91 to 360 days from the date of purchase. The Company receives interest at prevailing money market fund rates on its cash deposits.
	For the three and nine months ended September 30, 2013 and 2012, no single customer accounted for 10.0% or more of the Company’s operating revenues.

Recent_Accounting_Standards_Up

Recent Accounting Standards Updates	9 Months Ended
	Sep. 30, 2013
Accounting Changes And Error Corrections [Abstract]	'
Recent Accounting Standards Updates	'
	2. RECENT ACCOUNTING STANDARDS UPDATES
	In February 2013, the FASB issued Accounting Standards Update No. 2013-02, “Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income,” or ASU 2013-02. The amendments in this update require an entity to provide information about the amounts reclassified from accumulated other comprehensive income by component. In addition, an entity is required to present, either on the face of the income statement or in the notes thereto, significant amounts reclassified from accumulated other comprehensive income by the respective net income line item. This new guidance is to be applied prospectively for interim and annual periods beginning after December 15, 2012. The adoption of ASU 2013-02 did not have a material impact on the Company’s unaudited condensed consolidated financial statements.
	In July 2013, the FASB issued Accounting Standards Update No. 2013-10, “Inclusion of the Fed Funds Effective Swap Rate (or Overnight Index Swap Rate) as a Benchmark Interest Rate for Hedge Accounting Purposes,” or ASU 2013-10. The amendments in this update permit the Fed Funds Effective Swap Rate (OIS) to be used as a U.S. benchmark interest rate for hedge accounting purposes under ASC Topic 815, “Derivatives and Hedging,” in addition to the interest rates on direct Treasury obligations of the U.S. government and LIBOR. The amendments also remove the restriction on using different benchmark rates for similar hedges. This new guidance is to be applied prospectively for qualifying new or redesignated hedging relationships entered into on or after July 17, 2013. The adoption of ASU 2013-10 is not expected to have a material impact on the Company’s unaudited condensed consolidated financial statements.
	In July 2013, the FASB issued Accounting Standards Update No. 2013-11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists,” or ASU 2013-11. The amendments in this update require that an unrecognized tax benefit, or a portion of an unrecognized tax benefit, be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except under a few limited circumstances. The amendments in this update do not require new recurring disclosures. This new guidance is to be applied prospectively for interim and annual periods beginning after December 15, 2013. The adoption of ASU 2013-11 is not expected to have a material impact on the Company’s unaudited condensed consolidated financial statements.

Reclassifications_Out_of_Accum

Reclassifications Out of Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2013
Statement Of Income And Comprehensive Income [Abstract]	'
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)	'
	3. RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
	As required by ASC Subtopic 220-10, “Comprehensive Income—Overall,” the following table presents the amounts reclassified from accumulated other comprehensive income (loss) by the respective line item in the Unaudited Condensed Consolidated Statements of Income:
	Reclassifications Out of Accumulated Other Comprehensive Income (Loss)(1)
	(in thousands)
	Details about Accumulated Other Comprehensive Income		Amount Reclassified from Accumulated						Affected Line Item in the
	(Loss) Components		Other Comprehensive Income (Loss)						Unaudited Condensed
									Consolidated Statement of
									Income
			Three Months			Nine Months
			Ended			Ended
			September 30,			September 30,
			2013			2013
	Unrealized losses on cash flow hedges
	Interest rate contracts		$	(197	)	$	(1,364	)	Interest expense
				77			524		Tax benefit
			$	(120	)	$	(840	)	Net of tax
	Unrealized gains on available-for-sale securities
	Short-term investments		$	—		$	5		Interest income
				—			(2	)	Tax expense
			$	—		$	3		Net of tax
	Total reclassifications for the period, net of tax		$	(120	)	$	(837	)
	(1)	Amounts in parentheses indicate expenses or losses moved to the Unaudited Condensed Consolidated Statements of Income.

Earnings_Per_Common_Share

Earnings Per Common Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Earnings Per Common Share	'
	4. EARNINGS PER COMMON SHARE
	Basic earnings per share (“EPS”) is computed by dividing income available to MSCI common shareholders by the weighted average number of common shares outstanding during the period. Shares of common stock outstanding include common stock and vested restricted stock unit awards where recipients have satisfied either the explicit vesting terms or retirement-eligible requirements. Diluted EPS reflects the assumed conversion of all dilutive securities. There were 1,133 and 453 anti-dilutive securities excluded from the calculation of diluted EPS for the three and nine months ended September 30, 2013, respectively. There were no anti-dilutive securities excluded from the calculation of diluted EPS for the three months ended September 30, 2012. There were 2,903 anti-dilutive securities excluded from the calculation of diluted EPS for the nine months ended September 30, 2012.
	The Company computes EPS using the two-class method and determines whether instruments granted in share-based payment transactions are participating securities. The following table presents the computation of basic and diluted EPS:
			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2013			2012			2013			2012
			(in thousands, except per share data)
	Net income		$	55,310		$	48,274		$	175,300		$	129,786
	Less: Allocations of earnings to unvested restricted stock units (1)			(211	)		(304	)		(668	)		(818	)
	Earnings available to MSCI common shareholders		$	55,099		$	47,970		$	174,632		$	128,968
	Basic weighted average common shares outstanding			119,607			122,261			120,497			122,016
	Basic weighted average common shares outstanding			119,607			122,261			120,497			122,016
	Effect of dilutive securities:
	Stock options and restricted stock units			971			1,189			949			1,271
	Diluted weighted average common shares outstanding			120,578			123,450			121,446			123,287
	Earnings per basic common share		$	0.46		$	0.39		$	1.45		$	1.06
	Earnings per diluted common share		$	0.46		$	0.39		$	1.44		$	1.05
	(1)	Restricted stock units granted to employees prior to 2013 and all restricted stock units granted to independent directors of the Company have a right to participate in all of the earnings of the Company in the computation of basic EPS and, therefore, these restricted stock units are not included as incremental shares in the diluted EPS computation.

ShortTerm_Investments

Short-Term Investments	9 Months Ended
	Sep. 30, 2013
Investments Debt And Equity Securities [Abstract]	'
Short-Term Investments	'
	5. SHORT-TERM INVESTMENTS
	In the nine months ended September 30, 2013, the Company began investing excess cash in money market funds and other similar cash equivalents rather than in U.S. Treasury securities and other short-term investments as it had in prior periods. As a result, the Company held no short-term investments as of September 30, 2013.
	The fair value and gross unrealized gains and losses of securities available-for-sale as of December 31, 2012 were as follows:
	(in thousands)	Amortized		Gross		Gross		Estimated
		Cost plus		unrealized		unrealized		Fair
		Accrued		gains		losses		value
		Interest
	Debt securities available-for-sale
	U.S. Treasury securities	$	70,893	$	5	$	—	$	70,898
	There were no investments with continuous unrealized losses for less than 12 months as of December 31, 2012.

Property_Equipment_and_Leaseho

Property, Equipment and Leasehold Improvements	9 Months Ended
	Sep. 30, 2013
Property Plant And Equipment [Abstract]	'
Property, Equipment and Leasehold Improvements	'
	6. PROPERTY, EQUIPMENT AND LEASEHOLD IMPROVEMENTS
	Property, equipment and leasehold improvements at September 30, 2013 and December 31, 2012 consisted of the following:
			As of
	Type	Estimated	September 30,			December 31,
		Useful Lives	2013			2012
			(in thousands)
	Computer & related equipment	3 to 5 years	$	83,708		$	67,529
	Furniture & fixtures	7 years		8,182			7,847
	Leasehold improvements	3 to 21 years		50,573			48,405
	Work-in-process	—		5,202			2,716
	Subtotal			147,665			126,497
	Accumulated depreciation and amortization			(73,856	)		(59,078	)
	Property, equipment and leasehold improvements, net		$	73,809		$	67,419
	Depreciation and amortization expense of property, equipment and leasehold improvements was $5.9 million and $4.6 million for the three months ended September 30, 2013 and 2012, respectively. Depreciation and amortization expense of property, equipment and leasehold improvements was $16.3 million and $13.7 million for the nine months ended September 30, 2013 and 2012, respectively.

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'
Goodwill and Intangible Assets	'
	7. GOODWLL AND INTANGIBLE ASSETS
	Goodwill
	The Company carries goodwill as a result of its acquisitions of Barra, LLC (“Barra”), RiskMetrics Group, LLC (“RiskMetrics”), Measurisk, LLC (“Measurisk”), IPD Group Limited (“IPD”) and Investor Force Holdings, Inc. (“InvestorForce”), as reflected in the table below:
			Performance			Governance			Total
			and Risk
	(in thousands)
	Goodwill at December 31, 2012 (1)		$	1,530,849		$	252,561		$	1,783,410
	Changes to goodwill (2)			14,370			(468	)		13,902
	Foreign exchange translation adjustment			(89	)		—			(89	)
	Goodwill at September 30, 2013		$	1,545,130		$	252,093		$	1,797,223
	-1	During the three months ended September 30, 2013, the Company identified an error in the deferred tax allocation between its operating segments dating back to the June 1, 2010 acquisition of RiskMetrics. The Company determined that a deferred tax liability that was reflected as a component of the Performance and Risk segment’s books should have been recorded on the Governance segment’s books. The adjustment decreases the net deferred tax liability and goodwill value of the Performance and Risk segment’s books by $21.4 million while increasing the net deferred tax liability and goodwill on the Governance segments books by an offsetting $21.4 million. The correction was made during the three months ended September 30, 2013 and the goodwill at December 31, 2012 has been adjusted to reflect the correct allocations between the operating segments. The correction did not have an effect on the Company’s unaudited condensed consolidated financial statements or segment results of operations for any period.
	(2)	Resulting from the acquisition of InvestorForce, which contributed $11.6 million to the Performance and Risk segment, adjustments to the valuation of acquired IPD assets and liabilities, which contributed $2.7 million to the Performance and Risk segment, and the disposal of the CFRA product line, which removed $0.5 million from the Governance segment.
	Intangible Assets
	Amortization expense related to intangible assets for the three months ended September 30, 2013 and 2012 was $14.4 million and $16.0 million, respectively. Amortization expense related to intangible assets for the nine months ended September 30, 2013 and 2012 was $43.4 million and $47.9 million, respectively.
	The gross carrying amounts, accumulated amortization and net carrying values related to the Company’s identifiable intangible assets are as follows:
			As of
	(in thousands)		September 30,			December 31,
			2013			2012
	Gross intangible assets:
	Customer relationships		$	478,735		$	474,236
	Trademarks/trade names			257,282			256,582
	Technology/software			198,322			193,192
	Proprietary process			3,800			3,800
	Proprietary data			28,527			28,527
	Subtotal			966,666			956,337
	Foreign exchange translation adjustment			613			836
	Total gross intangible assets		$	967,279		$	957,173
	Accumulated amortization:
	Customer relationships		$	(117,166	)	$	(92,631	)
	Trademarks/trade names			(72,291	)		(62,270	)
	Technology/software			(166,030	)		(159,375	)
	Proprietary process			(2,111	)		(1,636	)
	Proprietary data			(1,772	)		(184	)
	Subtotal			(359,370	)		(316,096	)
	Foreign exchange translation adjustment			(143	)		(3	)
	Total accumulated amortization		$	(359,513	)	$	(316,099	)
	Net intangible assets:
	Customer relationships		$	361,569		$	381,605
	Trademarks/trade names			184,991			194,312
	Technology/software			32,292			33,817
	Proprietary process			1,689			2,164
	Proprietary data			26,755			28,343
	Subtotal			607,296			640,241
	Foreign exchange translation adjustment			470			833
	Total net intangible assets		$	607,766		$	641,074
	The estimated amortization expense for succeeding years is presented below:
	Fiscal Year		Amortization Expense
			(in thousands)
	Remainder of 2013		$	14,481
	2014			58,086
	2015			58,169
	2016			56,032
	2017			49,918
	2018			47,379
	Thereafter			323,701
	Total		$	607,766

Commitments_and_Contingencies

Commitments and Contingencies

9 Months Ended

Sep. 30, 2013

Commitments And Contingencies Disclosure [Abstract]

'

Commitments and Contingencies

'

8. COMMITMENTS AND CONTINGENCIES

Legal matters. From time to time, the Company is party to various litigation matters incidental to the conduct of its business. The Company is not presently party to any legal proceedings the resolution of which the Company believes would have a material effect on its business, operating results, financial condition or cash flows.

Leases. The Company leases facilities under non-cancelable operating lease agreements. The terms of certain lease agreements provide for rental payments on a graduated basis. The Company recognizes rent expense on the straight-line basis over the lease period and has accrued for rent expense incurred but not paid. Rent expense for the three months ended September 30, 2013 and 2012 was $6.5 million and $6.0 million, respectively. Rent expense for the nine months ended September 30, 2013 and 2012 was $18.9 million and $19.0 million, respectively.

Share repurchase. On December 13, 2012, the Board of Directors approved a stock repurchase program authorizing the purchase of up to $300.0 million worth of shares of MSCI’s common stock beginning immediately and continuing through December 31, 2014 (the “2012 Repurchase Program”). As part of this authorization, on December 13, 2012, the Company entered into an accelerated share repurchase (“ASR”) agreement with a financial institution to initiate share repurchases aggregating $100.0 million (the “December 2012 ASR Program”). The December 2012 ASR Program was structured as a capped ASR in which the Company paid $100.0 million and received approximately 2.2 million shares on December 14, 2012, representing the minimum number of common shares to be repurchased based on a calculation using a specific capped price per share. On July 31, 2013, the Company completed the December 2012 ASR Program, receiving an additional 0.8 million shares. In total, 3.0 million shares were delivered to MSCI for an average purchase price of $33.47 per share. The repurchased shares are held in treasury.

On August 1, 2013, MSCI entered into a new ASR agreement to initiate share repurchases aggregating $100.0 million (the “August 2013 ASR Program”). The August 2013 ASR Program is structured as a capped ASR in which, on August 2, 2013, MSCI paid $100.0 million and received approximately 1.9 million shares, representing the minimum number of common shares to be repurchased based on a calculation using a specific capped price per share. This price is capped such that only under limited circumstances may the Company be required to deliver shares or pay cash at settlement. The repurchased shares are held in treasury. The Company anticipates that all repurchases under the August 2013 ASR Program will be completed no later than the final repurchase date in December 2013, although settlement of the August 2013 ASR Program may be accelerated under certain circumstances. Additionally, depending on the average share price through the completion date in December 2013, MSCI may receive additional shares under the August 2013 ASR Program.

The $100.0 million payment for the August 2013 ASR Program was initially split and recorded as a $70.0 million increase to “Treasury stock” and a $30.0 million decrease to “Additional paid in capital” on the Company’s Unaudited Condensed Consolidated Statement of Financial Condition to reflect the initial estimate of the value of shares received. The 2012 Repurchase Program, except for the ASR, may be modified, suspended, terminated or extended by the Company at any time without prior notice. The remaining $100.0 million balance authorized under the 2012 Repurchase Program will be available for utilization through December 31, 2014 at the Company’s discretion.

Long-term debt. On June 1, 2010, the Company entered into a senior secured credit agreement comprised of (i) a six-year term loan facility (the “2010 Term Loan”) and (ii) a five-year revolving credit facility (the revolving credit facility, together with the 2010 Term Loan, the “2010 Credit Facility”).

On March 14, 2011, the Company completed the repricing of the 2010 Credit Facility pursuant to Amendment No. 2 to the 2010 Credit Facility (“Amendment No. 2”). Amendment No. 2 provided for the incurrence of a new senior secured term loan (the “2011 Term Loan”). The proceeds of the 2011 Term Loan, together with cash on hand, were used to repay the remaining outstanding balance of the 2010 Term Loan in full. The 2011 Term Loan was to mature in March 2017.

On May 4, 2012, the Company amended and restated its 2010 Credit Facility (the credit agreement as so amended and restated, the “Amended and Restated Credit Facility”). The Amended and Restated Credit Facility provides for the incurrence of a new senior secured five-year Term Loan A Facility in an aggregate amount of $880.0 million (the “2012 Term Loan”) and a $100.0 million senior secured revolving facility (the “2012 Revolving Credit Facility”). The proceeds of the Amended and Restated Credit Facility, together with cash on hand, were used to repay the remaining outstanding principal of the then-existing 2011 Term Loan. The 2012 Term Loan and the 2012 Revolving Credit Facility mature on May 4, 2017. The Company is required to repay 5.00% per annum of the 2012 Term Loan in quarterly payments over the first two years, 10.00% per annum of the 2012 Term Loan in quarterly payments over the next two years, and 70.00% of the 2012 Term Loan in quarterly payments over the final year.

The 2012 Term Loan bears interest equal to the London Interbank Offered Rate (“LIBOR”) plus a margin. As of September 30, 2013, the 2012 Term Loan bore interest at LIBOR plus a margin of 2.00%, or 2.18%. In March 2013, the Company made a $15.0 million prepayment on the 2012 Term Loan.

Current maturities of long-term debt at September 30, 2013 was $54.1 million, net of a $0.9 million discount. Long-term debt, net of current maturities at September 30, 2013 was $753.3 million, net of a $1.7 million discount.

Current maturities of long-term debt at December 31, 2012 was $43.1 million, net of a $0.9 million discount. Long-term debt, net of current maturities at December 31, 2012 was $811.6 million, net of a $2.4 million discount.

In connection with entering into the Amended and Restated Credit Facility, the Company paid $5.7 million in fees, $3.9 million of which are being deferred. These financing fees, together with the existing fees related to prior credit facilities, are being amortized over the life of the Amended and Restated Credit Facility. At September 30, 2013, $8.4 million of the deferred financing fees remain unamortized, $2.7 million of which is included in “Prepaid and other assets” and $5.7 million of which is included in “Other non-current assets” on the Company’s Unaudited Condensed Consolidated Statement of Financial Condition.

The Company amortized $0.7 million and $0.5 million of deferred financing fees in interest expense during the three months ended September 30, 2013 and 2012, respectively. The Company amortized $2.2 million and $17.1 million of deferred financing fees in interest expense during the nine months ended September 30, 2013 and 2012, respectively. Approximately $0.2 million of debt discount was amortized in interest expense during each of the three months ended September 30, 2013 and 2012. Approximately $0.7 million and $5.1 million of debt discount were amortized in interest expense during the nine months ended September 30, 2013 and 2012, respectively.

At September 30, 2013 and December 31, 2012, the fair market value of the Company’s debt obligations were $813.0 million and $862.3 million, respectively. The fair market value is determined in accordance with accounting standards related to the determination of fair value as discussed in Note 9, “Fair Value Measures,” and represents Level 2 valuations. The Company utilizes the market approach and obtains security pricing from a vendor who uses broker quotes and third-party pricing services to determine fair values.

The Amended and Restated Credit Facility also amended certain negative covenants, including financial covenants.

As of September 30, 2013, the Company’s retained earnings of $723.0 million were restricted as to the payments of dividends. As outlined in the Amended and Restated Credit Facility, the Company cannot pay or declare any dividends except out of amounts available for restricted payments. As of September 30, 2013, the amount available for restricted payments was $355.7 million, reflecting the Company’s cumulative retained excess cash flows (“CRECF”), as defined in the Amended and Restated Credit Facility, through December 31, 2012 and adjusted for any restricted payments made during the nine months ended September 30, 2013. To the extent the CRECF is utilized for other actions restricted under the Amended and Restated Credit Facility, including stock repurchases, the amount available for restricted payments will be reduced.

Derivatives and Hedging Activities. The Company is exposed to certain risks arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate, liquidity, and credit risk primarily by managing the amount, sources, and duration of its debt funding and the use of derivative financial instruments. Specifically, the Company had previously entered into derivative financial instruments to manage exposures that arose from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates, and may do so again in the future. The Company’s derivative financial instruments were used to manage differences in the amount, timing and duration of the Company’s known or expected cash payments principally related to the Company’s borrowings.

Certain of the Company’s foreign operations expose the Company to fluctuations of foreign exchange rates. These fluctuations may impact the value of the Company’s cash receipts and payments in terms of the Company’s functional currency, the U.S. dollar. The Company enters into derivative financial instruments to protect the value or fix the amount of certain obligations in terms of its functional currency.

Cash Flow Hedges of Interest Rate Risk. As a result of the repayment of the 2011 Term Loan on May 4, 2012 and the 2010 Term Loan on March 14, 2011, the Company discontinued prospective hedge accounting on its then-existing interest rate swaps as they no longer met hedge accounting requirements. The Company has not entered into new interest rate swaps to hedge its debt and it is not required to do so under the Amended and Restated Credit Facility. The Company continued to report the net loss related to the discontinued cash flow hedges in Accumulated Other Comprehensive Income (Loss) and reclassified this amount into earnings through the contractual term of the swap agreements which ended in August 2013.

Non-designated Hedges of Foreign Exchange Risk. Derivatives not designated as hedges are not speculative and are used to manage the Company’s exposure to foreign exchange rate movements but do not meet the strict hedge accounting requirements. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings. As of September 30, 2013, the Company had three outstanding foreign currency forwards with a combined notional amount of $40.5 million that were not designated as hedges in qualifying hedging relationships.

The following table presents the fair values of the Company’s derivative instruments and the location in which they are presented on the Company’s Unaudited Condensed Consolidated Statements of Financial Condition:

(in thousands)

Unaudited Condensed

As of

As of

Consolidated Statements of

September 30, 2013

December 31, 2012

Financial Condition Location

Derivatives designated as hedging instruments:

Liability derivatives:

Foreign exchange contracts

Other accrued liabilities

$

(1,349

)

$

(203

)

Asset derivatives:

Foreign exchange contracts

Prepaid and other assets

$

—

$

3

The following tables present the effect of the Company’s financial derivatives and the location in which they are presented on the Company’s Unaudited Condensed Consolidated Statements of Financial Condition and Unaudited Condensed Consolidated Statements of Income:

Derivatives in Cash Flow Hedging

Amount of Gain or

Location of Gain or

Amount of Gain or

Location of Gain or

Amount of Gain or

Relationships

(Loss) Recognized

(Loss) Reclassified

(Loss) Reclassified

(Loss) Recognized

(Loss) Recognized

in Accumulated

from Accumulated

from Accumulated

in Income on

in Income on

Other

Other

Other

Derivatives

Derivatives

Comprehensive

Comprehensive

Comprehensive

(Ineffective  Portion

(Ineffective Portion

Income (Loss)

Income into

Income (Loss)

and Amount

and Amount

on Derivatives

Income

into Income

Excluded from

Excluded from

(Effective Portion)

(Effective Portion)

(Effective Portion)

Effectiveness

Effectiveness

for the

for the

Testing)

Testing) for the

Three Months Ended

Three Months Ended

Three Months Ended

September 30,

September 30,

September 30,

(in thousands)

2013

2012

2013

2012

2013

2012

Interest rate swaps

$

—

$

—

Interest expense

$

(197

)

$

(610

)

Interest expense

$

—

$

—

Derivatives in Cash Flow Hedging

Amount of Gain or

Location of Gain or

Amount of Gain or

Location of Gain or

Amount of Gain or

Relationships

(Loss) Recognized

(Loss) Reclassified

(Loss) Reclassified

(Loss) Recognized

(Loss) Recognized

in Accumulated

from Accumulated

from Accumulated

in Income on

in Income on

Other

Other

Other

Derivatives

Derivatives

Comprehensive

Comprehensive

Comprehensive

(Ineffective Portion

(Ineffective Portion

Income (Loss)

Income (Loss) into

Income (Loss)

and Amount

and Amount

on Derivatives

Income

into Income

Excluded from

Excluded from

(Effective Portion)

(Effective Portion)

(Effective Portion)

Effectiveness

Effectiveness

for the

for the

Testing)

Testing) for the

Nine Months Ended

Nine Months Ended

Nine Months Ended

September 30,

September 30,

September 30,

(in thousands)

2013

2012

2013

2012

2013

2012

Interest rate swaps

$

—

$

(695

)

Interest expense

$

(1,364

)

$

(1,827

)

Interest expense

$

—

$

—

Derivatives Not Designated as Hedging Instruments

Location of Gain or

Amount of Gain or (Loss) Recognized

(in thousands)

(Loss) Recognized in

in Income on Derivatives for the

Income on Derivatives

Three Months Ended

September 30,

2013

2012

Foreign exchange contracts

Other expense

$

(1,472

)

$

—

Derivatives Not Designated as Hedging Instruments

Location of Gain or

Amount of Gain or (Loss) Recognized

(in thousands)

(Loss) Recognized in

in Income on Derivatives for the

Income on Derivatives

Nine Months Ended

September 30,

2013

2012

Foreign exchange contracts

Other expense

$

(185

)

$

—

Fair_Value_Measures

Fair Value Measures	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measures	'
	9. FAIR VALUE MEASURES
	The following table summarizes the Company’s financial assets and liabilities measured at fair value on a recurring basis as of September 30, 2013:
	Description	Balance as of			Quoted		Significant			Significant
		September 30,			Prices in		Other			Unobservable
		2013			Active		Observable			Inputs
					Markets		Inputs			(Level 3)
					for		(Level 2)
					Identical
					Assets
					(Level 1)
		(in thousands)
	Assets:
	Short-term investments	$	—		$	—	$	—		$	—
	Liabilities:
	Foreign exchange contracts	$	(1,349	)	$	—	$	(1,349	)	$	—
	The following table summarizes the Company’s financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2012:
	Description	Balance as of			Quoted		Significant			Significant
		December 31,			Prices in		Other			Unobservable
		2012			Active		Observable			Inputs
					Markets		Inputs			(Level 3)
					for		(Level 2)
					Identical
					Assets
					(Level 1)
		(in thousands)
	Assets:
	Short-term investments:
	U.S. Treasury securities	$	70,898		$	—	$	70,898		$	—
	Total short-term investments		70,898			—		70,898			—
	Foreign exchange contracts		3			—		3			—
	Total financial assets	$	70,901		$	—	$	70,901		$	—
	Liabilities:
	Foreign exchange contracts	$	(203	)	$	—	$	(203	)	$	—
	The Company’s financial assets and liabilities are valued using market prices on both active markets (Level 1) and less active markets (Level 2). The Company did not have any transfers between Level 1 and Level 2 fair value measurements during the periods presented. The Company does not hold any financial instruments that would be valued using Level 3 inputs as of the periods presented.
	The Company’s short-term investments consisted of U.S. Treasury securities and were classified within Level 2, as there was not an active market for these securities, but the market pricing data used to calculate the value of the instruments was derived from similar securities traded in active markets.
	The Company’s foreign exchange forward contracts were classified within Level 2, as they were valued using pricing models that took into account the contract terms as well as multiple observable inputs where applicable, such as prevailing spot rates and forward points.

Employee_Benefits

Employee Benefits	9 Months Ended
	Sep. 30, 2013
Compensation And Retirement Disclosure [Abstract]	'
Employee Benefits	'
	10. EMPLOYEE BENEFITS
	The Company sponsors a 401(k) plan for eligible U.S. employees and defined contribution and defined benefit pension plans that cover substantially all of its non-U.S. employees. Costs relating to 401(k), pension and post-retirement benefit expenses were $5.0 million and $3.6 million for the three months ended September 30, 2013 and 2012, respectively. Amounts included in cost of services were $3.4 million and $2.1 million for the three months ended September 30, 2013 and 2012, respectively. Amounts included in selling, general and administrative expense related to pension and post-retirement expenses for the three months ended September 30, 2013 and 2012 were $1.6 million and $1.5 million, respectively.
	For the nine months ended September 30, 2013 and 2012, costs relating to 401(k), pension and post-retirement benefit expenses were $16.9 million and $15.3 million, respectively. Amounts included in cost of services were $10.7 million and $9.7 million for the nine months ended September 30, 2013 and 2012, respectively. Amounts included in selling, general and administrative expense related to pension and post-retirement expenses for the nine months ended September 30, 2013 and 2012 were $6.2 million and $5.6 million, respectively.
	401(k) and Other Defined Contribution Plans. Eligible employees may participate in the MSCI 401(k) plan (or any other regional defined contribution plan sponsored by MSCI) immediately upon hire. Eligible employees receive 401(k) and other defined contribution plan matching contributions and, in the case of the MSCI 401(k) plan, an additional Company contribution of 3% of the employees’ cash compensation, which is subject to vesting and certain other limitations. The Company’s expenses associated with the 401(k) plan and other defined contribution plans were $4.3 million and $3.2 million for the three months ended September 30, 2013 and 2012, respectively. The Company’s expenses associated with the 401(k) plan and other defined contribution plans were $15.0 million and $12.8 million for the nine months ended September 30, 2013 and 2012, respectively.
	Net Periodic Benefit Expense. Net periodic benefit expense related to defined benefit pension plans was $0.7 million and $0.4 million for the three months ended September 30, 2013 and 2012, respectively. Net periodic benefit expense related to defined benefit pension plans was $1.9 million and $2.5 million for the nine months ended September 30, 2013 and 2012, respectively.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	11. INCOME TAXES
	The Company’s provision for income taxes was $85.8 million and $71.3 million for the nine months ended September 30, 2013 and 2012, respectively. These amounts reflect effective tax rates of 32.8% and 35.5% for the nine months ended September 30, 2013 and 2012, respectively. The effective rate of 32.8% for the nine months ended September 30, 2013 reflects the Company’s estimate of the effective tax rate for the period and is impacted by certain discrete items totaling $3.3 million, the effect of which was to decrease the Company’s effective tax rate by 2.2 percentage points.
	The Company is under examination by the Internal Revenue Service (“IRS”) and other tax authorities in certain countries, such as the United Kingdom, and in states in which the Company has significant business operations, such as New York. The tax years currently under examination vary by jurisdiction. During 2010, Morgan Stanley reached a settlement with New York State and New York City tax authorities on issues relating to tax years 2002 through 2006. During the year ended December 31, 2012, it was determined that MSCI’s share of the assessed tax and interest was $12.0 million, which the Company paid in accordance with the tax sharing agreement between it and Morgan Stanley, dated as of November 20, 2007. This reflected the final settlement of these tax issues with Morgan Stanley relating to tax years 2002 through 2006.
	The Company may have future settlements with Morgan Stanley related to the ultimate disposition of its New York State and New York City examination relating to the tax years 2007 through 2008 and its IRS examination relating to the tax years 2006 through 2008. The Company does not believe it has any material exposure for the New York State and New York City examination as the tax returns for those years were filed in a method consistent with the findings of the aforementioned settlement for the tax years 2002 through 2006. Additionally, the Company believes it has adequate reserves for any tax issues that may arise out of the IRS examination relating to the tax years 2006 through 2008 and therefore does not believe any related settlement with Morgan Stanley will have a material impact.
	The Company regularly assesses the likelihood of additional assessments in each of the taxing jurisdictions in which it files income tax returns. The Company has established unrecognized tax benefits that the Company believes are adequate in relation to the potential for additional assessments. Once established, the Company adjusts unrecognized tax benefits only when more information is available or when an event occurs necessitating a change. As part of the Company’s periodic review of unrecognized tax benefits and based on new information regarding the status of federal and state examinations, the Company’s unrecognized tax benefits were remeasured. It is reasonably possible that significant changes in the balance of unrecognized tax benefits may occur within the next 12 months. At this time, however, it is not possible to reasonably estimate the expected change to the total amount of unrecognized tax benefits and the impact on the effective tax rate over the next 12 months.
	The following table summarizes the major taxing jurisdictions in which the Company and its affiliates operate and the open tax years for each major jurisdiction:
	Tax Jurisdiction	Tax Years
	United States	2005-2012
	California	2009-2012
	New York State	2007-2011
	New York City	2007-2011
	Hong Kong	2006-2012
	United Kingdom	2010-2011
	Canada	2006-2012
	Japan	2009-2012
	India	2008-2012

Segment_Information

Segment Information	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]	'
Segment Information	'
	12. SEGMENT INFORMATION
	ASC Subtopic 280-10, “Segment Reporting,” establishes standards for reporting information about operating segments. Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by the chief operating decision maker, or CODM, in deciding how to allocate resources. MSCI’s Chief Executive Officer, who is considered to be its CODM, reviews financial information presented on an operating segment basis for purposes of making operating decisions and assessing financial performance. MSCI operates as two segments, the Performance and Risk business and the Governance business. These designations have been made as the discrete operating results of these segments are reviewed by the Company’s CODM for purposes of making operating decisions and assessing financial performance.
	The Performance and Risk business is a leading global provider of investment decision support tools, including equity indices, real estate indices and benchmarks, portfolio risk and performance analytics, credit analytics and ESG products. The business provides clients with a broad suite of products and services to assist them with managing equity, fixed income and multi-asset class portfolios. The products are used in many areas of the investment process, including portfolio construction and rebalancing, performance benchmarking and attribution, risk management and analysis, regulatory and client reporting, index-linked investment product creation, asset allocation, assessment of social responsibility, environmental stewardship and the effects of climate change on investments, investment manager selection and investment research.
	The Governance business is a leading provider of corporate governance products, services and data solutions to institutional investors and corporations around the world. Among other things, the Governance business facilitates the voting of proxies by institutional investors and provides in-depth research and analysis to help inform their voting decisions and identify issuer-specific risk. It offers both global equity security coverage and fully integrated products and services, including proxy voting, policy creation, research, vote recommendations, vote execution, post-vote disclosure and reporting and analytical tools. It also provides class action monitoring and claims filing services to aid institutional investors in the recovery of funds from securities class actions. Within a firewall, a separate unit of the Governance business also provides products and services to corporate clients who may use those products and services to learn about and improve their governance and executive compensation practices.
	Revenues and expenses directly associated with each respective segment are included in determining its operating results. Other expenses that are not directly attributable to a particular segment are allocated based upon allocation methodologies, including time estimates, headcount, net revenues and other relevant usage measures.
	The CODM does not review any information regarding total assets on an operating segment basis. Operating segments do not record intersegment revenue, and, accordingly, there is none to be reported. The accounting policies for segment reporting are the same as for MSCI as a whole.
	The following table presents MSCI’s operating segments’ results for the three and nine months ended September 30, 2013 and 2012:
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2013		2012		2013		2012
		(in thousands)
	Operating revenues
	Performance and Risk	$	228,608	$	205,389	$	676,500	$	611,054
	Governance		29,630		30,055		91,545		92,007
	Consolidated	$	258,238	$	235,444	$	768,045	$	703,061
	Amortization of intangible assets and depreciation and amortization of property, equipment and leasehold improvements
	Performance and Risk	$	16,038	$	16,393	$	46,843	$	49,053
	Governance		4,344		4,199		12,860		12,535
	Consolidated	$	20,382	$	20,592	$	59,703	$	61,588
	Operating income
	Performance and Risk	$	88,172	$	80,472	$	268,445	$	243,927
	Governance		4,264		3,057		11,690		7,702
	Consolidated	$	92,436	$	83,529	$	280,135	$	251,629
	Revenue by geography is based on the shipping address of the customer. The following table sets forth revenue for the periods indicated by geographic area:
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2013		2012		2013		2012
		(in thousands)
	Revenues
	Americas:
	United States	$	126,333	$	122,199	$	375,263	$	362,464
	Other		10,015		8,418		27,605		24,313
	Total Americas		136,348		130,617		402,868		386,777
	Europe, Middle East and Africa (“EMEA”):
	United Kingdom		38,502		28,127		111,303		84,337
	Other		53,190		45,639		164,172		139,559
	Total EMEA		91,692		73,766		275,475		223,896
	Asia & Australia:
	Japan		12,950		14,403		38,125		43,222
	Other		17,248		16,658		51,577		49,166
	Total Asia & Australia		30,198		31,061		89,702		92,388
	Total	$	258,238	$	235,444	$	768,045	$	703,061
	Long-lived assets consist of property, equipment, leasehold improvements, goodwill and intangible assets, net of accumulated depreciation and amortization.
	The following table sets forth long-lived assets on the dates indicated by geographic area:
		As of
		September 30,		December 31,
		2013		2012
		(in thousands)
	Long-lived assets
	Americas:
	United States	$	2,317,769	$	2,334,877
	Other		4,187		4,608
	Total Americas		2,321,956		2,339,485
	EMEA:
	United Kingdom		141,249		139,714
	Other		9,897		8,749
	Total EMEA		151,146		148,463
	Asia & Australia:
	Japan		253		297
	Other		5,443		3,658
	Total Asia & Australia		5,696		3,955
	Total	$	2,478,798	$	2,491,903

Acquisitions_and_Dispositions

Acquisitions and Dispositions	9 Months Ended
	Sep. 30, 2013
Business Combinations [Abstract]	'
Acquisitions and Dispositions	'
	13. ACQUISITIONS AND DISPOSITIONS
	The acquisition method of accounting is based on ASC Subtopic 805-10, “Business Combinations,” and uses the fair value concepts defined in ASC Subtopic 820-10, “Fair Value Measurements and Disclosures,” which the Company has adopted as required. The total purchase price is allocated to the net tangible and intangible assets based upon their fair values as of the acquisition dates. The excess of the purchase price over the fair values of the net tangible assets and intangible assets was recorded as goodwill. The allocation of the purchase price was based upon a valuation and is subject to change within the one-year measurement period following the acquisition. MSCI expects to continue to obtain information to assist it in determining the fair value of the net assets acquired at the acquisition date during the measurement period.
	Acquisition of IPD
	On November 30, 2012, MSCI Limited, an indirect wholly-owned subsidiary of the Company, paid cash of $124.8 million to acquire real estate performance measurement group IPD. The acquisition of IPD expands the Company’s multi-asset class offering by facilitating the integration of private real estate assets into its models, as well as adding a family of real estate indices to the Company’s family of equity indices. IPD is dedicated to the objective measurement of the commercial real estate market. Headquartered in London, with offices around the world, IPD is a leading provider of real estate performance analysis for funds, investors, managers, lenders and occupiers and offers a wide range of services that include research, reporting, benchmarking and indices. IPD has been added as a component of the Performance and Risk segment.
	As of September 30, 2013, the preliminary purchase price allocations for the IPD acquisition were $76.5 million for goodwill, $58.7 million for identifiable intangible assets, $18.6 million for assets other than identifiable intangible assets and $29.0 million for other liabilities.
	Acquisition of InvestorForce
	On January 29, 2013, MSCI completed the acquisition of InvestorForce by paying $23.6 million in cash. The acquisition of InvestorForce enhances MSCI’s position as a leader in performance analysis and risk transparency and furthers its goal of providing investment decision support tools to institutional investors across all client segments and asset classes. InvestorForce is a leading provider of performance reporting solutions to the institutional investment community in the United States, providing investment consultants with an integrated solution for daily monitoring, analysis and reporting on institutional assets. InvestorForce has been added as a component of the Performance and Risk segment.
	As of September 30, 2013, the preliminary purchase price allocations for the InvestorForce acquisition were $11.6 million for goodwill, $9.1 million for identifiable intangible assets, $6.4 million for assets other than identifiable intangible assets and $3.5 million for other liabilities. Primarily as a result of additional income tax information being received and a working capital adjustment, certain InvestorForce acquired tax asset values increased by $7.5 million and goodwill decreased by $7.4 million compared to those reported in the three months ended March 31, 2013.
	Disposition of CFRA
	On March 31, 2013, MSCI completed the sale of its CFRA product line, which was a component of the Governance segment. The results of operations from the CFRA product line and the sale of CFRA were not material to the Company.

Reclassifications_Out_of_Accum1

Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2013
Statement Of Income And Comprehensive Income [Abstract]	'
Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Loss)	'
	As required by ASC Subtopic 220-10, “Comprehensive Income—Overall,” the following table presents the amounts reclassified from accumulated other comprehensive income (loss) by the respective line item in the Unaudited Condensed Consolidated Statements of Income:
	Reclassifications Out of Accumulated Other Comprehensive Income (Loss)(1)
	(in thousands)
	Details about Accumulated Other Comprehensive Income		Amount Reclassified from Accumulated						Affected Line Item in the
	(Loss) Components		Other Comprehensive Income (Loss)						Unaudited Condensed
									Consolidated Statement of
									Income
			Three Months			Nine Months
			Ended			Ended
			September 30,			September 30,
			2013			2013
	Unrealized losses on cash flow hedges
	Interest rate contracts		$	(197	)	$	(1,364	)	Interest expense
				77			524		Tax benefit
			$	(120	)	$	(840	)	Net of tax
	Unrealized gains on available-for-sale securities
	Short-term investments		$	—		$	5		Interest income
				—			(2	)	Tax expense
			$	—		$	3		Net of tax
	Total reclassifications for the period, net of tax		$	(120	)	$	(837	)
	(1)	Amounts in parentheses indicate expenses or losses moved to the Unaudited Condensed Consolidated Statements of Income.

Earnings_Per_Common_Share_Tabl

Earnings Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Computation of Basic and Diluted EPS	'
	The following table presents the computation of basic and diluted EPS:
			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2013			2012			2013			2012
			(in thousands, except per share data)
	Net income		$	55,310		$	48,274		$	175,300		$	129,786
	Less: Allocations of earnings to unvested restricted stock units (1)			(211	)		(304	)		(668	)		(818	)
	Earnings available to MSCI common shareholders		$	55,099		$	47,970		$	174,632		$	128,968
	Basic weighted average common shares outstanding			119,607			122,261			120,497			122,016
	Basic weighted average common shares outstanding			119,607			122,261			120,497			122,016
	Effect of dilutive securities:
	Stock options and restricted stock units			971			1,189			949			1,271
	Diluted weighted average common shares outstanding			120,578			123,450			121,446			123,287
	Earnings per basic common share		$	0.46		$	0.39		$	1.45		$	1.06
	Earnings per diluted common share		$	0.46		$	0.39		$	1.44		$	1.05
	(1)	Restricted stock units granted to employees prior to 2013 and all restricted stock units granted to independent directors of the Company have a right to participate in all of the earnings of the Company in the computation of basic EPS and, therefore, these restricted stock units are not included as incremental shares in the diluted EPS computation.

ShortTerm_Investments_Tables

Short-Term Investments (Tables)	9 Months Ended
	Sep. 30, 2013
Investments Debt And Equity Securities [Abstract]	'
Summary of Fair Value and Gross Unrealized Gains and Losses of Debt Securities Available-for-Sale	'
	The fair value and gross unrealized gains and losses of securities available-for-sale as of December 31, 2012 were as follows:
	(in thousands)	Amortized		Gross		Gross		Estimated
		Cost plus		unrealized		unrealized		Fair
		Accrued		gains		losses		value
		Interest
	Debt securities available-for-sale
	U.S. Treasury securities	$	70,893	$	5	$	—	$	70,898

Property_Equipment_and_Leaseho1

Property, Equipment and Leasehold Improvements (Tables)	9 Months Ended
	Sep. 30, 2013
Property Plant And Equipment [Abstract]	'
Schedule of Property, Equipment and Leasehold Improvements	'
	Property, equipment and leasehold improvements at September 30, 2013 and December 31, 2012 consisted of the following:
			As of
	Type	Estimated	September 30,			December 31,
		Useful Lives	2013			2012
			(in thousands)
	Computer & related equipment	3 to 5 years	$	83,708		$	67,529
	Furniture & fixtures	7 years		8,182			7,847
	Leasehold improvements	3 to 21 years		50,573			48,405
	Work-in-process	—		5,202			2,716
	Subtotal			147,665			126,497
	Accumulated depreciation and amortization			(73,856	)		(59,078	)
	Property, equipment and leasehold improvements, net		$	73,809		$	67,419

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'
Schedule of Goodwill	'
	The Company carries goodwill as a result of its acquisitions of Barra, LLC (“Barra”), RiskMetrics Group, LLC (“RiskMetrics”), Measurisk, LLC (“Measurisk”), IPD Group Limited (“IPD”) and Investor Force Holdings, Inc. (“InvestorForce”), as reflected in the table below:
			Performance			Governance			Total
			and Risk
	(in thousands)
	Goodwill at December 31, 2012 (1)		$	1,530,849		$	252,561		$	1,783,410
	Changes to goodwill (2)			14,370			(468	)		13,902
	Foreign exchange translation adjustment			(89	)		—			(89	)
	Goodwill at September 30, 2013		$	1,545,130		$	252,093		$	1,797,223
	-1	During the three months ended September 30, 2013, the Company identified an error in the deferred tax allocation between its operating segments dating back to the June 1, 2010 acquisition of RiskMetrics. The Company determined that a deferred tax liability that was reflected as a component of the Performance and Risk segment’s books should have been recorded on the Governance segment’s books. The adjustment decreases the net deferred tax liability and goodwill value of the Performance and Risk segment’s books by $21.4 million while increasing the net deferred tax liability and goodwill on the Governance segments books by an offsetting $21.4 million. The correction was made during the three months ended September 30, 2013 and the goodwill at December 31, 2012 has been adjusted to reflect the correct allocations between the operating segments. The correction did not have an effect on the Company’s unaudited condensed consolidated financial statements or segment results of operations for any period.
	(2)	Resulting from the acquisition of InvestorForce, which contributed $11.6 million to the Performance and Risk segment, adjustments to the valuation of acquired IPD assets and liabilities, which contributed $2.7 million to the Performance and Risk segment, and the disposal of the CFRA product line, which removed $0.5 million from the Governance segment.
Components of Intangible Assets by Major Class	'
	The gross carrying amounts, accumulated amortization and net carrying values related to the Company’s identifiable intangible assets are as follows:
			As of
	(in thousands)		September 30,			December 31,
			2013			2012
	Gross intangible assets:
	Customer relationships		$	478,735		$	474,236
	Trademarks/trade names			257,282			256,582
	Technology/software			198,322			193,192
	Proprietary process			3,800			3,800
	Proprietary data			28,527			28,527
	Subtotal			966,666			956,337
	Foreign exchange translation adjustment			613			836
	Total gross intangible assets		$	967,279		$	957,173
	Accumulated amortization:
	Customer relationships		$	(117,166	)	$	(92,631	)
	Trademarks/trade names			(72,291	)		(62,270	)
	Technology/software			(166,030	)		(159,375	)
	Proprietary process			(2,111	)		(1,636	)
	Proprietary data			(1,772	)		(184	)
	Subtotal			(359,370	)		(316,096	)
	Foreign exchange translation adjustment			(143	)		(3	)
	Total accumulated amortization		$	(359,513	)	$	(316,099	)
	Net intangible assets:
	Customer relationships		$	361,569		$	381,605
	Trademarks/trade names			184,991			194,312
	Technology/software			32,292			33,817
	Proprietary process			1,689			2,164
	Proprietary data			26,755			28,343
	Subtotal			607,296			640,241
	Foreign exchange translation adjustment			470			833
	Total net intangible assets		$	607,766		$	641,074
Estimated Amortization Expense for Succeeding Years	'
	The estimated amortization expense for succeeding years is presented below:
	Fiscal Year		Amortization Expense
			(in thousands)
	Remainder of 2013		$	14,481
	2014			58,086
	2015			58,169
	2016			56,032
	2017			49,918
	2018			47,379
	Thereafter			323,701
	Total		$	607,766

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)

9 Months Ended

Sep. 30, 2013

Commitments And Contingencies Disclosure [Abstract]

'

Summary of Fair Values of Derivative Instruments

'

The following table presents the fair values of the Company’s derivative instruments and the location in which they are presented on the Company’s Unaudited Condensed Consolidated Statements of Financial Condition:

(in thousands)

Unaudited Condensed

As of

As of

Consolidated Statements of

September 30, 2013

December 31, 2012

Financial Condition Location

Derivatives designated as hedging instruments:

Liability derivatives:

Foreign exchange contracts

Other accrued liabilities

$

(1,349

)

$

(203

)

Asset derivatives:

Foreign exchange contracts

Prepaid and other assets

$

—

$

3

Interest Rate Swaps and Derivative Instruments

'

The following tables present the effect of the Company’s financial derivatives and the location in which they are presented on the Company’s Unaudited Condensed Consolidated Statements of Financial Condition and Unaudited Condensed Consolidated Statements of Income:

Derivatives in Cash Flow Hedging

Amount of Gain or

Location of Gain or

Amount of Gain or

Location of Gain or

Amount of Gain or

Relationships

(Loss) Recognized

(Loss) Reclassified

(Loss) Reclassified

(Loss) Recognized

(Loss) Recognized

in Accumulated

from Accumulated

from Accumulated

in Income on

in Income on

Other

Other

Other

Derivatives

Derivatives

Comprehensive

Comprehensive

Comprehensive

(Ineffective  Portion

(Ineffective Portion

Income (Loss)

Income into

Income (Loss)

and Amount

and Amount

on Derivatives

Income

into Income

Excluded from

Excluded from

(Effective Portion)

(Effective Portion)

(Effective Portion)

Effectiveness

Effectiveness

for the

for the

Testing)

Testing) for the

Three Months Ended

Three Months Ended

Three Months Ended

September 30,

September 30,

September 30,

(in thousands)

2013

2012

2013

2012

2013

2012

Interest rate swaps

$

—

$

—

Interest expense

$

(197

)

$

(610

)

Interest expense

$

—

$

—

Derivatives in Cash Flow Hedging

Amount of Gain or

Location of Gain or

Amount of Gain or

Location of Gain or

Amount of Gain or

Relationships

(Loss) Recognized

(Loss) Reclassified

(Loss) Reclassified

(Loss) Recognized

(Loss) Recognized

in Accumulated

from Accumulated

from Accumulated

in Income on

in Income on

Other

Other

Other

Derivatives

Derivatives

Comprehensive

Comprehensive

Comprehensive

(Ineffective Portion

(Ineffective Portion

Income (Loss)

Income (Loss) into

Income (Loss)

and Amount

and Amount

on Derivatives

Income

into Income

Excluded from

Excluded from

(Effective Portion)

(Effective Portion)

(Effective Portion)

Effectiveness

Effectiveness

for the

for the

Testing)

Testing) for the

Nine Months Ended

Nine Months Ended

Nine Months Ended

September 30,

September 30,

September 30,

(in thousands)

2013

2012

2013

2012

2013

2012

Interest rate swaps

$

—

$

(695

)

Interest expense

$

(1,364

)

$

(1,827

)

Interest expense

$

—

$

—

Derivatives Not Designated as Hedging Instruments

Location of Gain or

Amount of Gain or (Loss) Recognized

(in thousands)

(Loss) Recognized in

in Income on Derivatives for the

Income on Derivatives

Three Months Ended

September 30,

2013

2012

Foreign exchange contracts

Other expense

$

(1,472

)

$

—

Derivatives Not Designated as Hedging Instruments

Location of Gain or

Amount of Gain or (Loss) Recognized

(in thousands)

(Loss) Recognized in

in Income on Derivatives for the

Income on Derivatives

Nine Months Ended

September 30,

2013

2012

Foreign exchange contracts

Other expense

$

(185

)

$

—

Fair_Value_Measures_Tables

Fair Value Measures (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	'
	The following table summarizes the Company’s financial assets and liabilities measured at fair value on a recurring basis as of September 30, 2013:
	Description	Balance as of			Quoted		Significant			Significant
		September 30,			Prices in		Other			Unobservable
		2013			Active		Observable			Inputs
					Markets		Inputs			(Level 3)
					for		(Level 2)
					Identical
					Assets
					(Level 1)
		(in thousands)
	Assets:
	Short-term investments	$	—		$	—	$	—		$	—
	Liabilities:
	Foreign exchange contracts	$	(1,349	)	$	—	$	(1,349	)	$	—
	The following table summarizes the Company’s financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2012:
	Description	Balance as of			Quoted		Significant			Significant
		December 31,			Prices in		Other			Unobservable
		2012			Active		Observable			Inputs
					Markets		Inputs			(Level 3)
					for		(Level 2)
					Identical
					Assets
					(Level 1)
		(in thousands)
	Assets:
	Short-term investments:
	U.S. Treasury securities	$	70,898		$	—	$	70,898		$	—
	Total short-term investments		70,898			—		70,898			—
	Foreign exchange contracts		3			—		3			—
	Total financial assets	$	70,901		$	—	$	70,901		$	—
	Liabilities:
	Foreign exchange contracts	$	(203	)	$	—	$	(203	)	$	—

Income_Taxes_Tables

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Summary of Major Tax Jurisdictions and Open Tax Years	'
	The following table summarizes the major taxing jurisdictions in which the Company and its affiliates operate and the open tax years for each major jurisdiction:
	Tax Jurisdiction	Tax Years
	United States	2005-2012
	California	2009-2012
	New York State	2007-2011
	New York City	2007-2011
	Hong Kong	2006-2012
	United Kingdom	2010-2011
	Canada	2006-2012
	Japan	2009-2012
	India	2008-2012

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]	'
Key Financial Information by Operating Segments	'
	The following table presents MSCI’s operating segments’ results for the three and nine months ended September 30, 2013 and 2012:
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2013		2012		2013		2012
		(in thousands)
	Operating revenues
	Performance and Risk	$	228,608	$	205,389	$	676,500	$	611,054
	Governance		29,630		30,055		91,545		92,007
	Consolidated	$	258,238	$	235,444	$	768,045	$	703,061
	Amortization of intangible assets and depreciation and amortization of property, equipment and leasehold improvements
	Performance and Risk	$	16,038	$	16,393	$	46,843	$	49,053
	Governance		4,344		4,199		12,860		12,535
	Consolidated	$	20,382	$	20,592	$	59,703	$	61,588
	Operating income
	Performance and Risk	$	88,172	$	80,472	$	268,445	$	243,927
	Governance		4,264		3,057		11,690		7,702
	Consolidated	$	92,436	$	83,529	$	280,135	$	251,629
Revenue by Geographic Area	'
	The following table sets forth revenue for the periods indicated by geographic area:
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2013		2012		2013		2012
		(in thousands)
	Revenues
	Americas:
	United States	$	126,333	$	122,199	$	375,263	$	362,464
	Other		10,015		8,418		27,605		24,313
	Total Americas		136,348		130,617		402,868		386,777
	Europe, Middle East and Africa (“EMEA”):
	United Kingdom		38,502		28,127		111,303		84,337
	Other		53,190		45,639		164,172		139,559
	Total EMEA		91,692		73,766		275,475		223,896
	Asia & Australia:
	Japan		12,950		14,403		38,125		43,222
	Other		17,248		16,658		51,577		49,166
	Total Asia & Australia		30,198		31,061		89,702		92,388
	Total	$	258,238	$	235,444	$	768,045	$	703,061
Long-Lived Assets by Geographic Area	'
	The following table sets forth long-lived assets on the dates indicated by geographic area:
		As of
		September 30,		December 31,
		2013		2012
		(in thousands)
	Long-lived assets
	Americas:
	United States	$	2,317,769	$	2,334,877
	Other		4,187		4,608
	Total Americas		2,321,956		2,339,485
	EMEA:
	United Kingdom		141,249		139,714
	Other		9,897		8,749
	Total EMEA		151,146		148,463
	Asia & Australia:
	Japan		253		297
	Other		5,443		3,658
	Total Asia & Australia		5,696		3,955
	Total	$	2,478,798	$	2,491,903

Introduction_and_Basis_of_Pres1

Introduction and Basis of Presentation - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
			Segment
Introduction And Basis Of Presentation [Line Items]	'	'	'	'	'	'
Number of operating segments	'	'	2	'	'	'
Cumulative revenue reduction of one-time adjustment	'	'	'	$5,200,000	'	'
Cash and cash equivalents	283,750,000	340,458,000	283,750,000	340,458,000	183,309,000	252,211,000
U.S. Treasury Securities	'	'	'	'	$70,898,000	'
Percentage of operating revenues accounted for by major customer	10.00%	10.00%	10.00%	10.00%	'	'
Minimum [Member]	'	'	'	'	'	'
Introduction And Basis Of Presentation [Line Items]	'	'	'	'	'	'
Debt security maturity (days)	'	'	91	'	'	'
Maximum [Member]	'	'	'	'	'	'
Introduction And Basis Of Presentation [Line Items]	'	'	'	'	'	'
Debt security maturity (days)	'	'	360	'	'	'

Reclassifications_Out_of_Accum2

Reclassifications Out of Accumulated Other Comprehensive Income (Loss) - Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Interest expense	($5,827)	($7,314)	($19,351)	($49,250)
Tax benefit (expense)	-30,937	-27,320	-85,757	-71,308
Net income	55,310	48,274	175,300	129,786
Interest income	265	252	770	712
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) [Member]	'	'	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Net income	-120	'	-837	'
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) [Member] | Unrealized losses on cash flow hedges [Member]	'	'	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Tax benefit (expense)	77	'	524	'
Net income	-120	'	-840	'
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) [Member] | Unrealized losses on cash flow hedges [Member] | Interest rate swaps [Member]	'	'	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Interest expense	-197	'	-1,364	'
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) [Member] | Unrealized gains on available-for-sale securities [Member]	'	'	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Tax benefit (expense)	'	'	-2	'
Net income	'	'	3	'
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) [Member] | Unrealized gains on available-for-sale securities [Member] | Short-term investments [Member]	'	'	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Interest income	'	'	$5	'

Earnings_Per_Common_Share_Addi

Earnings Per Common Share - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]	'	'	'	'
Anti-dilutive stock options excluded from the calculation of diluted EPS	1,133	0	453	2,903

Earnings_Per_Common_Share_Comp

Earnings Per Common Share - Computation of Basic and Diluted EPS (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]	'	'	'	'
Net income	$55,310	$48,274	$175,300	$129,786
Less: Allocations of earnings to unvested restricted stock units	-211	-304	-668	-818
Earnings available to MSCI common shareholders	$55,099	$47,970	$174,632	$128,968
Basic weighted average common shares outstanding	119,607	122,261	120,497	122,016
Stock options and restricted stock units	971	1,189	949	1,271
Diluted weighted average common shares outstanding	120,578	123,450	121,446	123,287
Earnings per basic common share	$0.46	$0.39	$1.45	$1.06
Earnings per diluted common share	$0.46	$0.39	$1.44	$1.05

ShortTerm_Investments_Addition

Short-Term Investments - Additional Information (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Amortized Cost And Fair Value Debt Securities [Abstract]	'	'
Short-term investment held by company	'	$70,898

ShortTerm_Investments_Summary_

Short-Term Investments - Summary of Fair Value and Gross Unrealized Gains and Losses of Debt Securities Available-for-Sale (Detail) (U.S. Treasury securities [Member], USD $)	Dec. 31, 2012
In Thousands, unless otherwise specified
U.S. Treasury securities [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Amortized Cost plus Accrued Interest	$70,893
Gross unrealized gains	5
Gross unrealized losses	'
Estimated Fair value	$70,898

Property_Equipment_and_Leaseho2

Property, Equipment and Leasehold Improvements - Schedule of Property, Equipment and Leasehold Improvements (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
In Thousands, unless otherwise specified			Computer & related equipment [Member]	Computer & related equipment [Member]	Furniture & fixtures [Member]	Leasehold improvements [Member]	Leasehold improvements [Member]
			Minimum [Member]	Maximum [Member]		Minimum [Member]	Maximum [Member]
Property, Plant and Equipment [Line Items]	'	'	'	'	'	'	'
Estimated Useful Lives	'	'	'3 years	'5 years	'7 years	'3 years	'21 years
Computer & related equipment	$83,708	$67,529	'	'	'	'	'
Furniture & fixtures	8,182	7,847	'	'	'	'	'
Leasehold improvements	50,573	48,405	'	'	'	'	'
Work-in-process	5,202	2,716	'	'	'	'	'
Subtotal	147,665	126,497	'	'	'	'	'
Accumulated depreciation and amortization	-73,856	-59,078	'	'	'	'	'
Property, equipment and leasehold improvements, net	$73,809	$67,419	'	'	'	'	'

Property_Equipment_and_Leaseho3

Property, Equipment and Leasehold Improvements - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Property Plant And Equipment [Abstract]	'	'	'	'
Depreciation and amortization expense of property, equipment and leasehold improvements	$5,934	$4,633	$16,260	$13,711

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets - Schedule of Goodwill (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013
Goodwill [Line Items]	'
Goodwill, Beginning balance	$1,783,410
Changes to goodwill	13,902
Foreign exchange translation adjustment	-89
Goodwill, Ending balance	1,797,223
Performance and Risk [Member]	'
Goodwill [Line Items]	'
Goodwill, Beginning balance	1,530,849
Changes to goodwill	14,370
Foreign exchange translation adjustment	-89
Goodwill, Ending balance	1,545,130
Governance [Member]	'
Goodwill [Line Items]	'
Goodwill, Beginning balance	252,561
Changes to goodwill	-468
Goodwill, Ending balance	$252,093

Goodwill_and_Intangible_Assets3

Goodwill and Intangible Assets - Schedule of Goodwill (Parenthetical) (Detail) (USD $)	9 Months Ended			3 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
	Performance and Risk [Member]	Performance and Risk [Member]	Governance [Member]	Performance and Risk Segments Books [Member]	Governance Segments Books [Member]
	Investor Force Holdings, Inc. [Member]	IPD [Member]		Error Correction [Member]	Error Correction [Member]
Goodwill [Line Items]	'	'	'	'	'
Increase (decrease) in net deferred tax liability and goodwill value	'	'	'	($21.40)	$21.40
Adjustments to goodwill from acquisitions of IPD and InvestorForce	11.6	2.7	'	'	'
Adjustments to goodwill from sale of CFRA	'	'	$0.50	'	'

Goodwill_and_Intangible_Assets4

Goodwill and Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Goodwill And Intangible Assets Disclosure [Abstract]	'	'	'	'
Amortization expense	$14,448	$15,959	$43,443	$47,877

Goodwill_and_Intangible_Assets5

Goodwill and Intangible Assets - Components of Intangible Assets by Major Class (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	$967,279	$957,173
Accumulated amortization	-359,513	-316,099
Net carrying value	607,766	641,074
Subtotal [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	966,666	956,337
Accumulated amortization	-359,370	-316,096
Net carrying value	607,296	640,241
Customer relationships [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	478,735	474,236
Accumulated amortization	-117,166	-92,631
Net carrying value	361,569	381,605
Trademarks/trade names [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	257,282	256,582
Accumulated amortization	-72,291	-62,270
Net carrying value	184,991	194,312
Technology/software [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	198,322	193,192
Accumulated amortization	-166,030	-159,375
Net carrying value	32,292	33,817
Proprietary process [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	3,800	3,800
Accumulated amortization	-2,111	-1,636
Net carrying value	1,689	2,164
Proprietary data [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	28,527	28,527
Accumulated amortization	-1,772	-184
Net carrying value	26,755	28,343
Foreign exchange translation adjustment [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	613	836
Accumulated amortization	-143	-3
Net carrying value	$470	$833

Goodwill_and_Intangible_Assets6

Goodwill and Intangible Assets - Estimated Amortization Expense for Succeeding Years (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Goodwill And Intangible Assets Disclosure [Abstract]	'	'
Remainder of 2013	$14,481	'
2014	58,086	'
2015	58,169	'
2016	56,032	'
2017	49,918	'
2018	47,379	'
Thereafter	323,701	'
Total	$607,766	$641,074

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)

1 Months Ended

3 Months Ended

9 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

9 Months Ended

1 Months Ended

3 Months Ended

Share data in Millions, except Per Share data, unless otherwise specified

4-May-12

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2012

Dec. 13, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Mar. 14, 2011

Sep. 30, 2013

Jul. 31, 2013

Dec. 14, 2012

Aug. 02, 2013

Sep. 30, 2013

4-May-12

4-May-12

Mar. 31, 2013

Sep. 30, 2013

Sep. 30, 2013

Instruments

Instruments

Foreign currency forwards [Member]

Treasury stock [Member]

Additional paid in capital [Member]

Prepaid and other assets [Member]

Other non-current assets [Member]

2011 Term Loan [Member]

December 2012 ASR Program [Member]

December 2012 ASR Program [Member]

December 2012 ASR Program [Member]

August 2013 ASR Program [Member]

Amended and Restated Credit Facility [Member]

Term Loan A [Member]

Senior Secured Revolving Facility [Member]

Term Loan [Member]

Term Loan [Member]

Term Loan [Member]

Derivatives Not Designated as Hedging Instruments [Member]

Accelerated Share Repurchase Program [Member]

Accelerated Share Repurchase Program [Member]

Accelerated Share Repurchase Program [Member]

Accelerated Share Repurchase Program [Member]

Amended and Restated Credit Facility [Member]

Amended and Restated Credit Facility [Member]

Minimum [Member]

Maximum [Member]

Schedule Of Commitments And Contingencies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Annual rent expense

'

$6,500,000

$6,000,000

$18,900,000

$19,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Repurchase program authorizing the purchase of shares

'

'

'

'

'

'

300,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares repurchases, value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100,000,000

100,000,000

'

'

'

'

'

'

Repurchased common shares

'

'

'

'

'

'

'

'

'

'

'

'

'

3

0.8

2.2

1.9

'

'

'

'

'

'

Repurchased common shares, average purchase price paid per share

'

'

'

'

'

'

'

'

'

'

'

'

'

$33.47

'

'

'

'

'

'

'

'

'

Stockholders equity period increase decrease

'

'

'

100,000,000

'

'

'

'

70,000,000

30,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Remaining stock to be repurchased

'

'

'

100,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maturity period of the facility

'

'

'

'

'

'

'

'

'

'

'

'

1-Mar-17

'

'

'

'

'

4-May-17

4-May-17

'

'

'

Aggregate amount of debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

880,000,000

100,000,000

'

'

'

Debt principal repayment over first two years

5.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt principal repayment over next two years

10.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt principal repayment over final year

70.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Prepayment of Term Loan

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

15,000,000

'

'

Initial bearing interest rate, percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2.00%

2.18%

Current maturities of long-term debt

'

54,130,000

'

54,130,000

'

43,093,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Discount on long-term debt current

'

900,000

'

900,000

'

900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt, net of current maturities

'

753,285,000

'

753,285,000

'

811,623,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Discount on long-term debt non current

'

1,700,000

'

1,700,000

'

2,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amended and Restated Credit Facility fee paid

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,700,000

'

'

'

'

'

Deferred financing fees

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,900,000

'

'

'

'

'

Deferred financing fees unamortized

'

8,400,000

'

8,400,000

'

'

'

'

'

'

2,700,000

5,700,000

'

'

'

'

'

'

'

'

'

'

'

Amortized deferred financing fees

'

700,000

500,000

2,200,000

17,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amortized debt discount

'

200,000

200,000

699,000

5,072,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair market value of debt obligations

'

813,000,000

'

813,000,000

'

862,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Retained earnings were restricted as to the payments of dividends

'

722,999,000

'

722,999,000

'

547,699,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amount available for restricted payments

'

'

'

355,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of foreign currency forwards

'

3

'

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Foreign currency forwards, notional amount

'

'

'

'

'

'

'

$40,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Commitments_and_Contingencies_2

Commitments and Contingencies - Summary of Fair Values of Derivative Instruments (Detail) (Derivatives designated as hedging instruments [Member], Foreign exchange contracts [Member], USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Other accrued liabilities [Member]	'	'
Commitments And Contingencies [Line Items]	'	'
Liability derivatives	($1,349)	($203)
Prepaid and other assets [Member]	'	'
Commitments And Contingencies [Line Items]	'	'
Asset derivatives	'	$3

Commitments_and_Contingencies_3

Commitments and Contingencies - Interest Rate Swaps and Derivative Instruments (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Interest expense [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) into Income (Effective Portion)	($197)	($610)	($1,364)	($1,827)
Amount of Gain or (Loss) Recognized in Income on Derivatives (Ineffective Portion and Amount Excluded from Effectiveness Testing)	'	'	'	'
Other expense [Member] | Derivatives Not Designated as Hedging Instruments [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount of Gain or (Loss) Recognized in Accumulated Other Comprehensive Income on Derivatives (Effective Portion)	-1,472	'	-185	'
Interest rate swaps [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount of Gain or (Loss) Recognized in Accumulated Other Comprehensive Income (Loss) on Derivatives (Effective Portion)	'	'	'	($695)

Fair_Value_Measures_Summary_of

Fair Value Measures - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investments	'	$70,898
Foreign exchange contracts	'	3
Total financial assets	'	70,901
Foreign exchange contracts	-1,349	-203
U.S. Treasury securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investments	'	70,898
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investments	'	'
Foreign exchange contracts	'	'
Total financial assets	'	'
Foreign exchange contracts	'	'
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. Treasury securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investments	'	'
Significant Other Observable Inputs (Level 2) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investments	'	70,898
Foreign exchange contracts	'	3
Total financial assets	'	70,901
Foreign exchange contracts	-1,349	-203
Significant Other Observable Inputs (Level 2) [Member] | U.S. Treasury securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investments	'	70,898
Significant Unobservable Inputs (Level 3) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investments	'	'
Foreign exchange contracts	'	'
Total financial assets	'	'
Foreign exchange contracts	'	'
Significant Unobservable Inputs (Level 3) [Member] | U.S. Treasury securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short-term investments	'	'

Employee_Benefits_Additional_I

Employee Benefits - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Employee Benefit Plans [Line Items]	'	'	'	'
Pension and post-retirement benefit expenses	$5	$3.60	$16.90	$15.30
Percentage of additional contribution from the Company to employees' cash compensation	'	'	3.00%	'
Defined contribution plan expenses	4.3	3.2	15	12.8
Net periodic benefit expense	0.7	0.4	1.9	2.5
Cost of services [Member]	'	'	'	'
Employee Benefit Plans [Line Items]	'	'	'	'
Pension and post-retirement benefit expenses	3.4	2.1	10.7	9.7
Selling, general and administrative [Member]	'	'	'	'
Employee Benefit Plans [Line Items]	'	'	'	'
Pension and post-retirement benefit expenses	$1.60	$1.50	$6.20	$5.60

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Income Taxes And Tax Related [Line Items]	'	'	'	'	'
Provision for income taxes	$30,937,000	$27,320,000	$85,757,000	$71,308,000	'
Effective tax rate	'	'	32.80%	35.50%	'
Amounts effect on effective tax rate	3,300,000	'	3,300,000	'	'
Decrease in effective tax rate	'	'	2.20%	'	'
Reserve to indemnify tax settlement	'	'	'	'	$12,000,000
Significant change in unrecognized tax benefits, reasonably possible (in months)	'	'	'12	'	'
Significant change in unrecognized tax benefits, not possible (in months)	'	'	'12	'	'
New York State and City [Member] | Minimum [Member]	'	'	'	'	'
Income Taxes And Tax Related [Line Items]	'	'	'	'	'
Tax years under examination	'	'	'2002	'	'
New York State and City [Member] | Maximum [Member]	'	'	'	'	'
Income Taxes And Tax Related [Line Items]	'	'	'	'	'
Tax years under examination	'	'	'2006	'	'
Morgan Stanley [Member] | New York State and City [Member] | Minimum [Member]	'	'	'	'	'
Income Taxes And Tax Related [Line Items]	'	'	'	'	'
Tax years under examination	'	'	'2007	'	'
Morgan Stanley [Member] | New York State and City [Member] | Maximum [Member]	'	'	'	'	'
Income Taxes And Tax Related [Line Items]	'	'	'	'	'
Tax years under examination	'	'	'2008	'	'
Morgan Stanley [Member] | Internal Revenue Service (IRS) [Member] | Minimum [Member]	'	'	'	'	'
Income Taxes And Tax Related [Line Items]	'	'	'	'	'
Tax years under examination	'	'	'2006	'	'
Morgan Stanley [Member] | Internal Revenue Service (IRS) [Member] | Maximum [Member]	'	'	'	'	'
Income Taxes And Tax Related [Line Items]	'	'	'	'	'
Tax years under examination	'	'	'2008	'	'

Income_Taxes_Summary_of_Major_

Income Taxes - Summary of Major Tax Jurisdictions and Open Tax Years (Detail)	9 Months Ended
	Sep. 30, 2013
United States [Member]	'
Income Tax [Line Items]	'
Tax Years	'2005-2012
California [Member]	'
Income Tax [Line Items]	'
Tax Years	'2009-2012
New York State [Member]	'
Income Tax [Line Items]	'
Tax Years	'2007-2011
New York City [Member]	'
Income Tax [Line Items]	'
Tax Years	'2007-2011
Hong Kong [Member]	'
Income Tax [Line Items]	'
Tax Years	'2006-2012
United Kingdom [Member]	'
Income Tax [Line Items]	'
Tax Years	'2010-2011
Canada [Member]	'
Income Tax [Line Items]	'
Tax Years	'2006-2012
Japan [Member]	'
Income Tax [Line Items]	'
Tax Years	'2009-2012
India [Member]	'
Income Tax [Line Items]	'
Tax Years	'2008-2012

Segment_Information_Additional

Segment Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2013
	Segment
Segment Reporting [Abstract]	'
Number of operating segments	2

Segment_Information_Key_Financ

Segment Information - Key Financial Information by Operating Segments (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]	'	'	'	'
Operating revenues	$258,238	$235,444	$768,045	$703,061
Amortization of intangible assets and depreciation and amortization of property, equipment and leasehold improvements	20,382	20,592	59,703	61,588
Operating income	92,436	83,529	280,135	251,629
Operating Segments [Member] | Performance and Risk [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Operating revenues	228,608	205,389	676,500	611,054
Amortization of intangible assets and depreciation and amortization of property, equipment and leasehold improvements	16,038	16,393	46,843	49,053
Operating income	88,172	80,472	268,445	243,927
Operating Segments [Member] | Governance [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Operating revenues	29,630	30,055	91,545	92,007
Amortization of intangible assets and depreciation and amortization of property, equipment and leasehold improvements	4,344	4,199	12,860	12,535
Operating income	$4,264	$3,057	$11,690	$7,702

Segment_Information_Revenue_by

Segment Information - Revenue by Geographic Area (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Schedule Of Geographical Information [Line Items]	'	'	'	'
Revenues	$258,238	$235,444	$768,045	$703,061
Reportable Geographical Components [Member] | United States [Member]	'	'	'	'
Schedule Of Geographical Information [Line Items]	'	'	'	'
Revenues	126,333	122,199	375,263	362,464
Reportable Geographical Components [Member] | Other [Member]	'	'	'	'
Schedule Of Geographical Information [Line Items]	'	'	'	'
Revenues	10,015	8,418	27,605	24,313
Reportable Geographical Components [Member] | Total Americas [Member]	'	'	'	'
Schedule Of Geographical Information [Line Items]	'	'	'	'
Revenues	136,348	130,617	402,868	386,777
Reportable Geographical Components [Member] | United Kingdom [Member]	'	'	'	'
Schedule Of Geographical Information [Line Items]	'	'	'	'
Revenues	38,502	28,127	111,303	84,337
Reportable Geographical Components [Member] | Other [Member]	'	'	'	'
Schedule Of Geographical Information [Line Items]	'	'	'	'
Revenues	53,190	45,639	164,172	139,559
Reportable Geographical Components [Member] | Total EMEA [Member]	'	'	'	'
Schedule Of Geographical Information [Line Items]	'	'	'	'
Revenues	91,692	73,766	275,475	223,896
Reportable Geographical Components [Member] | Japan [Member]	'	'	'	'
Schedule Of Geographical Information [Line Items]	'	'	'	'
Revenues	12,950	14,403	38,125	43,222
Reportable Geographical Components [Member] | Other [Member]	'	'	'	'
Schedule Of Geographical Information [Line Items]	'	'	'	'
Revenues	17,248	16,658	51,577	49,166
Reportable Geographical Components [Member] | Total Asia & Australia [Member]	'	'	'	'
Schedule Of Geographical Information [Line Items]	'	'	'	'
Revenues	$30,198	$31,061	$89,702	$92,388

Segment_Information_LongLived_

Segment Information - Long-Lived Assets by Geographic Area (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Geographic Information For Property Plant And Equipment [Line Items]	'	'
Long-lived assets	$2,478,798	$2,491,903
Reportable Geographical Components [Member] | United States [Member]	'	'
Geographic Information For Property Plant And Equipment [Line Items]	'	'
Long-lived assets	2,317,769	2,334,877
Reportable Geographical Components [Member] | Other [Member]	'	'
Geographic Information For Property Plant And Equipment [Line Items]	'	'
Long-lived assets	4,187	4,608
Reportable Geographical Components [Member] | Total Americas [Member]	'	'
Geographic Information For Property Plant And Equipment [Line Items]	'	'
Long-lived assets	2,321,956	2,339,485
Reportable Geographical Components [Member] | United Kingdom [Member]	'	'
Geographic Information For Property Plant And Equipment [Line Items]	'	'
Long-lived assets	141,249	139,714
Reportable Geographical Components [Member] | Other [Member]	'	'
Geographic Information For Property Plant And Equipment [Line Items]	'	'
Long-lived assets	9,897	8,749
Reportable Geographical Components [Member] | Total EMEA [Member]	'	'
Geographic Information For Property Plant And Equipment [Line Items]	'	'
Long-lived assets	151,146	148,463
Reportable Geographical Components [Member] | Japan [Member]	'	'
Geographic Information For Property Plant And Equipment [Line Items]	'	'
Long-lived assets	253	297
Reportable Geographical Components [Member] | Other [Member]	'	'
Geographic Information For Property Plant And Equipment [Line Items]	'	'
Long-lived assets	5,443	3,658
Reportable Geographical Components [Member] | Total Asia & Australia [Member]	'	'
Geographic Information For Property Plant And Equipment [Line Items]	'	'
Long-lived assets	$5,696	$3,955

Acquisitions_and_Dispositions_

Acquisitions and Dispositions - Additional Information (Detail) (USD $)	9 Months Ended		1 Months Ended	9 Months Ended	1 Months Ended	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Nov. 30, 2012	Sep. 30, 2013	Jan. 29, 2013	Sep. 30, 2013
			IPD [Member]	IPD [Member]	Investor Force Holdings, Inc. [Member]	Investor Force Holdings, Inc. [Member]
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items]	'	'	'	'	'	'
Company paid cash to acquire property	'	'	$124,800,000	'	$23,600,000	'
Date of acquisition	'	'	'	30-Nov-12	'	29-Jan-13
Purchase price allocated to goodwill	1,797,223,000	1,783,410,000	'	76,500,000	'	11,600,000
Purchase price allocated to identifiable intangible assets	'	'	'	58,700,000	'	9,100,000
Purchase price allocated for assets other than identifiable intangible assets	'	'	'	18,600,000	'	6,400,000
Purchase price allocated to other liabilities	'	'	'	29,000,000	'	3,500,000
Increase in tax asset	'	'	'	'	'	7,500,000
Decrease in goodwill	$13,902,000	'	'	'	'	$7,400,000