MSCI (MSCI) 10-Q 30 Oct 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2014	Oct. 24, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
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	'	112,030,366

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Financial Condition (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
ASSETS	'	'
Cash and cash equivalents	$448,193	$358,434
Accounts receivable (net of allowances of $789 and $1,280 at September 30, 2014 and December 31, 2013, respectively)	191,806	169,490
Deferred taxes	52,124	52,888
Prepaid taxes	35,027	14,568
Prepaid and other assets	31,439	28,890
Total current assets	758,589	624,270
Property, equipment and leasehold improvements (net of accumulated depreciation and amortization of $93,011 and $75,371 at September 30, 2014 and December 31, 2013, respectively)	93,787	85,588
Goodwill	1,567,443	1,813,164
Intangible assets (net of accumulated amortization of $360,927 and $374,377 at September 30, 2014 and December 31, 2013, respectively)	445,034	595,707
Other non-current assets	15,426	17,386
Total assets	2,880,279	3,136,115
LIABILITIES AND SHAREHOLDERS' EQUITY	'	'
Accounts payable	1,695	1,198
Accrued compensation and related benefits	91,840	121,124
Other accrued liabilities	64,298	41,212
Current maturities of long-term debt	19,781	19,772
Deferred revenue	321,025	319,735
Total current liabilities	498,639	503,041
Long-term debt, net of current maturities	773,173	788,010
Deferred taxes	171,681	234,649
Other non-current liabilities	40,252	46,068
Total liabilities	1,483,745	1,571,768
Commitments and Contingencies (see Note 8)	'	'
Shareholders' equity:	'	'
Preferred stock (par value $0.01; 100,000,000 shares authorized; no shares issued)	0	0
Common stock (par value $0.01; 750,000,000 common shares authorized; 126,586,553 and 125,555,268 common shares issued and 112,027,156 and 118,083,111 common shares outstanding at September 30, 2014 and December 31, 2013, respectively)	1,266	1,256
Treasury shares, at cost (14,559,397 and 7,472,157 common shares held at September 30, 2014 and December 31, 2013, respectively)	-588,119	-268,391
Additional paid in capital	1,017,305	1,073,157
Retained earnings	978,358	758,975
Accumulated other comprehensive income (loss)	-12,276	-650
Total shareholders' equity	1,396,534	1,564,347
Total liabilities and shareholders' equity	$2,880,279	$3,136,115

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Financial Condition (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Accounts receivable, allowances	$789	$1,280
Property, equipment and leasehold improvements, accumulated depreciation and amortization	93,011	75,371
Intangible assets, accumulated amortization	$360,927	$374,377
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	126,586,553	125,555,268
Common stock, shares outstanding	112,027,156	118,083,111
Treasury shares	14,559,397	7,472,157

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, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]	'	'	'	'
Operating revenues	$251,661	$228,608	$745,575	$676,500
Operating expenses:	'	'	'	'
Cost of services	78,876	68,151	231,119	203,147
Selling, general and administrative	70,833	59,917	210,007	168,274
Amortization of intangible assets	11,574	11,193	34,286	33,581
Depreciation and amortization of property, equipment and leasehold improvements	6,342	5,443	18,091	14,814
Total operating expenses	167,625	144,704	493,503	419,816
Operating income	84,036	83,904	252,072	256,684
Interest income	-277	-227	-625	-650
Interest expense	5,604	5,828	16,029	19,343
Other expense (income)	-1,287	563	-942	2,157
Other expense (income), net	4,040	6,164	14,462	20,850
Income from continuing operations before provision for income taxes	79,996	77,740	237,610	235,834
Provision for income taxes	28,272	27,804	81,937	76,799
Income from continuing operations	51,724	49,936	155,673	159,035
Income (loss) from discontinued operations, net of income taxes	-10	5,374	84,100	16,265
Net income	$51,714	$55,310	$239,773	$175,300
Earnings per basic common share:	'	'	'	'
Earnings per basic common share from continuing operations	$0.44	$0.42	$1.33	$1.32
Earnings per basic common share from discontinued operations	'	$0.04	$0.72	$0.13
Earnings per basic common share	$0.44	$0.46	$2.05	$1.45
Earnings per diluted common share:	'	'	'	'
Earnings per diluted common share from continuing operations	$0.44	$0.42	$1.32	$1.31
Earnings per diluted common share from discontinued operations	'	$0.04	$0.71	$0.13
Earnings per diluted common share	$0.44	$0.46	$2.03	$1.44
Weighted average shares outstanding used in computing earnings per share:	'	'	'	'
Basic	116,251	119,607	116,840	120,497
Diluted	117,163	120,578	117,803	121,446

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]	'	'	'	'
Net income	$51,714	$55,310	$239,773	$175,300
Other comprehensive income (loss):	'	'	'	'
Foreign currency translation adjustments	-10,266	6,522	-11,992	-1,252
Income tax effect	-502	-2,519	163	479
Foreign currency translation adjustments, net	-10,768	4,003	-11,829	-773
Unrealized gains (losses) on cash flow hedges	'	197	'	1,364
Income tax effect	'	-77	'	-524
Unrealized gains (losses) on cash flow hedges, net	'	120	'	840
Unrealized gains (losses) on available-for-sale securities	'	'	'	-5
Income tax effect	'	'	'	2
Unrealized gains (losses) on available-for-sale securities, net	'	'	'	-3
Pension and other post-retirement adjustments	53	-68	219	47
Income tax effect	-18	17	-16	-16
Pension and other post-retirement adjustments, net	35	-51	203	31
Other comprehensive income (loss), net of tax	-10,733	4,072	-11,626	95
Comprehensive income	$40,981	$59,382	$228,147	$175,395

Condensed_Consolidated_Stateme4

Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities	'	'
Net income	$239,773	$175,300
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Amortization of intangible assets	37,026	43,443
Stock-based compensation expense	20,116	19,150
Depreciation and amortization of property, equipment and leasehold improvements	18,310	16,260
Amortization of debt origination fees	1,328	2,179
Deferred taxes	996	-2,125
Amortization of discount on long-term debt	359	699
Excess tax benefits from stock-based compensation	-3,197	-1,766
Gain on disposition of subsidiary, net of costs	-84,620	'
Other non-cash adjustments	1,764	-748
Changes in assets and liabilities, net of assets and liabilities acquired:	'	'
Accounts receivable	-38,635	-26,762
Prepaid income taxes	-20,552	-13,067
Prepaid and other assets	-7,343	-3,393
Accounts payable	973	-2,017
Deferred revenue	50,304	25,454
Accrued compensation and related benefits	-19,581	-16,161
Other accrued liabilities	6,552	3,147
Other	-1,954	6,444
Net cash provided by operating activities	201,619	226,037
Cash flows from investing activities	'	'
Proceeds from redemption of short-term investments	'	70,900
Acquisitions, net of cash acquired	-14,880	-23,268
Dispositions, net of cash provided	362,811	'
Proceeds from the sale of capital equipment	8	29
Capitalized software development costs	-6,063	-1,829
Capital expenditures	-36,174	-20,899
Net cash provided by investing activities	305,702	24,933
Cash flows from financing activities	'	'
Repayment of long-term debt	-15,187	-48,000
Repurchase of treasury shares	-409,396	-109,928
Proceeds from exercise of stock options	9,009	9,308
Excess tax benefits from stock-based compensation	3,197	1,766
Net cash used in financing activities	-412,377	-146,854
Effect of exchange rate changes	-5,185	-3,675
Net increase in cash and cash equivalents	89,759	100,441
Cash and cash equivalents, beginning of period	358,434	183,309
Cash and cash equivalents, end of period	448,193	283,750
Supplemental disclosure of cash flow information:	'	'
Cash paid for interest	14,387	15,099
Cash paid for income taxes	101,421	99,642
Supplemental disclosure of non-cash investing activities:	'	'
Property, equipment and leasehold improvements in other accrued liabilities	$3,929	$5,219

Introduction_and_Basis_of_Pres

Introduction and Basis of Presentation	9 Months Ended
	Sep. 30, 2014
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 indexes, portfolio risk and performance analytics. The Company’s flagship products are its global equity indexes and environmental, social and governance (“ESG”) products marketed under the MSCI and MSCI ESG Research brands, its private real estate benchmarks marketed under the IPD brand, 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 performance reporting products and services offered to the investment consultant community marketed under the InvestorForce brand and its valuation models and risk management software for the energy and commodities markets marketed under the FEA brand.
	On March 17, 2014, MSCI entered into a definitive agreement to sell Institutional Shareholder Services Inc. (“ISS”). As a result, the Company reported the operating results of ISS in “Income from discontinued operations, net of income taxes” in the Unaudited Condensed Consolidated Statements of Income for the three and nine months ended September 30, 2014 and 2013. As a result of this change, the Company now operates as one segment. Unless otherwise indicated, the disclosures accompanying these unaudited condensed consolidated financial statements reflect the Company’s continuing operations.
	The Company completed the sale of ISS on April 30, 2014. See Note 3, “Dispositions and Discontinued Operations,” for further details.
	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, 2014 and December 31, 2013, the results of operations and comprehensive income for the three and nine months ended September 30, 2014 and 2013 and cash flows for the nine months ended September 30, 2014 and 2013. 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, 2013. The unaudited condensed consolidated financial statement information as of December 31, 2013 has been derived from the 2013 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. Certain prior period amounts have been reclassified to conform to the current year financial statement presentation.
	Revision
	In connection with the preparation of the Company’s unaudited condensed consolidated financial statements for the three months ended June 30, 2014, the Company determined that it had understated its net tax liabilities in certain years prior to December 31, 2012. As a result of these errors, the Company has recorded the following corrections as of December 31, 2013: (i) an $11.3 million decrease to beginning retained earnings, (ii) a $0.7 million decrease to additional paid in capital, (iii) a $12.8 million decrease to prepaid taxes, (iv) a $13.6 million increase to long-term deferred tax liabilities and (v) a $14.3 million increase to goodwill. In accordance with the accounting guidance found in Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Subtopic 250-10, “Accounting Changes and Error Corrections,” the Company has revised its Unaudited Condensed Consolidated Statements of Financial Condition as of December 31, 2013 to reflect these corrections. The Company will revise all other previously reported results as such financial information is included in future filings.
	In accordance with SEC Staff Accounting Bulletin No. 99, “Materiality,” the Company assessed the materiality of the adjustments and concluded that these corrections were not material to any of its previously issued financial statements. The Company also concluded that its compliance with debt covenants would not have been affected by these adjustments.
	Accordingly, the Company has revised the Unaudited Condensed Consolidated Statement of Financial Condition as of December 31, 2013 from amounts previously reported as follows:
		(in thousands)
		As Previously		Adjustment			As Revised
		Reported
	Prepaid taxes	$	27,333	$	(12,765	)	$	14,568
	Total current assets	$	637,035	$	(12,765	)	$	624,270
	Goodwill	$	1,798,821	$	14,343		$	1,813,164
	Total assets	$	3,134,537	$	1,578		$	3,136,115
	Deferred taxes	$	221,054	$	13,595		$	234,649
	Total liabilities	$	1,558,173	$	13,595		$	1,571,768
	Additional paid in capital	$	1,073,893	$	(736	)	$	1,073,157
	Retained earnings	$	770,256	$	(11,281	)	$	758,975
	Total shareholders’ equity	$	1,576,364	$	(12,017	)	$	1,564,347
	Total liabilities and shareholders’ equity	$	3,134,537	$	1,578		$	3,136,115
	Concentrations
	Financial instruments that may potentially subject the Company to concentration risk consist principally of cash deposits. At September 30, 2014 and December 31, 2013, cash and cash equivalent amounts were $448.2 million and $358.4 million, respectively. The Company receives interest at prevailing money market fund rates on its cash deposits.
	For the nine months ended September 30, 2014, BlackRock, Inc. accounted for 10.6% of the Company’s operating revenues. For the nine months ended September 30, 2013, 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, 2014
Accounting Changes and Error Corrections [Abstract]	'
Recent Accounting Standards Updates	'
	2. RECENT ACCOUNTING STANDARDS UPDATES
	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 has been applied prospectively for interim and annual periods beginning after December 15, 2013. The adoption of ASU 2013-11 did not have a material impact on the Company’s unaudited condensed consolidated financial statements.
	In April 2014, the FASB issued Accounting Standards Update No. 2014-08, “Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity,” or ASU 2014-08. The amendments in this update change the requirements for reporting discontinued operations under ASC Subtopic 205-20, “Presentation of Financial Statements – Discontinued Operations,” such as limiting discontinued operations reporting to disposals of components of an entity that represent strategic shifts that have (or will have) a major effect on an entity’s operations and financial results. The amendments in this update also require expanded disclosures in order to provide users of financial statements with more information about the assets, liabilities, revenues and expenses of discontinued operations. Further, the amendments require an entity to disclose the pretax profit or loss of an individually significant component of an entity that does not qualify for discontinued operations reporting. This new guidance is to be applied prospectively for annual periods beginning on or after December 15, 2014, and interim periods within those years, with early adoption permitted. The Company has elected not to early adopt ASU 2014-08 and is evaluating the potential impact that the update will have on its unaudited condensed consolidated financial statements.
	In May 2014, the FASB issued Accounting Standards Update No. 2014-09, “Revenue from Contracts with Customers,” or ASU 2014-09. The objective of ASU 2014-09 is to establish a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and will supersede most of the existing revenue recognition guidance, including industry-specific guidance. The core principle of ASU 2014-09 is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In applying the new guidance, an entity will (1) identify the contract(s) with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the contract’s performance obligations; and (5) recognize revenue when, or as, the entity satisfies a performance obligation. The new guidance is effective for annual reporting periods (including interim periods within those periods) beginning after December 15, 2016 for public companies. Early adoption is not permitted. Entities have the option of using either a full retrospective or modified approach to adopt ASU 2014-09. The Company is evaluating the potential impact that the update will have on its unaudited condensed consolidated financial statements.

Dispositions_and_Discontinued_

Dispositions and Discontinued Operations	9 Months Ended
	Sep. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]	'
Dispositions and Discontinued Operations	'
	3. DISPOSITIONS AND DISCONTINUED OPERATIONS
	Disposition of CFRA
	On March 31, 2013, MSCI completed the sale of its CFRA product line. The value of the disposed assets and liabilities and the resulting gain on disposal were not material to the Company.
	Disposition of ISS
	On March 17, 2014, MSCI entered into a definitive agreement to sell ISS. The results of operations from ISS and the CFRA product line are reflected in “Income from discontinued operations, net of income taxes” in the Unaudited Condensed Consolidated Statements of Income.
	The sale of ISS was completed on April 30, 2014 for $367.4 million. The value of the assets and liabilities of ISS that were disposed, directly attributable transaction costs and the resulting gain on disposal that has been reported in “Income from discontinued operations, net of income taxes” for the three and nine months ended September 30, 2014 are as follows:
	(in thousands)
	Cash proceeds	$	367,355
	Less: Working capital adjustments		(311	)
	Total proceeds		367,044
	Less assets sold and liabilities relieved resulting from disposal:
	Cash and cash equivalents		(4,544	)
	Accounts receivable		(15,765	)
	Deferred taxes (current)		(3,174	)
	Prepaid taxes		(617	)
	Prepaid and other assets		(4,500	)
	Property, equipment and leasehold improvements (net of accumulated depreciation and amortization of $4,213)		(8,544	)
	Goodwill		(254,233	)
	Intangible assets (net of accumulated amortization of $50,283)		(121,269	)
	Other non-current assets		(1,645	)
	Accounts payable		574
	Accrued compensation and related benefits		6,783
	Other accrued liabilities		4,034
	Deferred revenue		51,767
	Deferred taxes (non-current)		59,129
	Other non-current liabilities		5,576
	Other comprehensive income including currency translation adjustments and pension and other post-retirement adjustments		4,004
	Net assets sold		(282,424	)
	Less: Transaction costs		(5,946	)
	Gain on sale of ISS	$	78,674
	Income (loss) from discontinued operations. Amounts associated with discontinued operations reflected in the Unaudited Condensed Consolidated Statements of Income for the three months ended September 30, 2014 and 2013 are as follows:
		Three Months Ended
		September 30,
		2014			2013
		(in thousands)
	Revenue from discontinued operations	$	—		$	29,630
	Income (loss) from discontinued operations before provision (benefit) for income taxes	$	(110	)	$	8,507
	Provision (benefit) for income taxes		(100	)		3,133
	Income (loss) from discontinued operations, net of income taxes	$	(10	)	$	5,374
	Amounts associated with discontinued operations reflected in the Unaudited Condensed Consolidated Statements of Income for the nine months ended September 30, 2014 and 2013 are as follows:
		Nine Months Ended
		September 30,
		2014			2013
		(in thousands)
	Revenue from discontinued operations	$	43,122		$	91,545
	Income from discontinued operations before provision for income taxes	$	86,254		$	25,223
	Provision for income taxes		2,154			8,958
	Income from discontinued operations, net of income taxes	$	84,100		$	16,265
	The three months ended March 31, 2014 included a $30.6 million income tax benefit associated with establishing a net deferred tax asset on the difference between the ISS tax basis and book basis. This net deferred tax asset was realized in the three months ended June 30, 2014 upon the closing of the sale, which reflects the tax basis capital loss realized on this book gain.

Reclassifications_out_of_Accum

Reclassifications out of Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]	'
Reclassifications out of Accumulated Other Comprehensive Income (Loss)	'
	4. RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
	As required by FASB’s ASC Subtopic 220-10, “Comprehensive Income—Overall,” the following tables present the amounts reclassified from Accumulated other comprehensive income (loss) by the respective line item in the Unaudited Condensed Consolidated Statements of Income for the three and nine months ended September 30, 2014 and 2013.
	Reclassifications Out of Accumulated Other Comprehensive Income (Loss)(1)
	(in thousands)
	Details about Accumulated Other		Amount Reclassified from Accumulated Other						Affected Line Item in the
	Comprehensive Income (Loss)		Comprehensive Income (Loss)						Unaudited Condensed
	Components								Consolidated Statements of
									Income
			Three Months Ended			Three Months Ended
			September 30,			September 30,
			2014			2013
	Unrealized losses on cash flow hedges Interest rate contracts		$	—		$	(197	)	Interest expense
				—			77		Tax benefit
			$	—		$	(120	)	Net of tax
	Unrealized gains on available-for-sale securities
	Short-term investments		$	—		$	—		Interest income
				—			—		Tax expense
			$	—		$	—		Net of tax
	Defined benefit pension plans
	Amount recognized as a component of net periodic benefit expense for curtailments and settlements		$	—		$	—		-2
				—			—		Tax expense
			$	—		$	—		Net of tax
	Foreign currency translation adjustment		$	—		$	—		-2
	Total reclassifications for the period, net of tax		$	—		$	(120	)
	(1)	Amounts in parentheses indicate expenses or losses moved to the Unaudited Condensed Consolidated Statements of Income.
	(2)	These accumulated other comprehensive income components were reclassified to “Income from discontinued operations, net of taxes” as part of the gain on the disposition of ISS.
	Reclassifications Out of Accumulated Other Comprehensive Income (Loss)(1)
	(in thousands)
	Details about Accumulated Other		Amount Reclassified from Accumulated Other						Affected Line Item in the
	Comprehensive Income (Loss)		Comprehensive Income (Loss)						Unaudited Condensed
	Components								Consolidated Statements of
									Income
			Nine Months Ended			Nine Months Ended
			September 30,			September 30,
			2014			2013
	Unrealized losses on cash flow hedges Interest rate contracts		$	—		$	(1,364	)	Interest expense
				—			524		Tax benefit
			$	—		$	(840	)	Net of tax
	Unrealized gains on available-for-sale securities
	Short-term investments		$	—		$	5		Interest income
				—			(2	)	Tax expense
			$	—		$	3		Net of tax
	Defined benefit pension plans
	Amount recognized as a component of net periodic benefit expense for curtailments and settlements		$	(186	)	$	—		-2
				6			—		Tax expense
			$	(180	)	$	—		Net of tax
	Foreign currency translation adjustment		$	4,184		$	—		-2
	Total reclassifications for the period, net of tax		$	4,004		$	(837	)
	(1)	Amounts in parentheses indicate expenses or losses moved to the Unaudited Condensed Consolidated Statements of Income.
	(2)	These accumulated other comprehensive income components were reclassified to “Income from discontinued operations, net of taxes” as part of the gain on the disposition of ISS.

Earnings_Per_Common_Share

Earnings Per Common Share	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Earnings Per Common Share	'
	5. 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. Common shares 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 104,494 and 104,346 stock options excluded from the calculation of diluted EPS for the three and nine months ended September 30, 2014, respectively, because of their anti-dilutive effect. 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.
	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,
			2014			2013			2014			2013
	(in thousands, except per share data)
	Income from continuing operations, net of income taxes		$	51,724		$	49,936		$	155,673		$	159,035
	Income (loss) from discontinued operations, net of income taxes			(10	)		5,374			84,100			16,265
	Net income		$	51,714		$	55,310		$	239,773		$	175,300
	Less: Allocations of earnings to unvested restricted stock units (1)			(69	)		(211	)		(320	)		(668	)
	Earnings available to MSCI common shareholders		$	51,645		$	55,099		$	239,453		$	174,632
	Basic weighted average common shares outstanding			116,251			119,607			116,840			120,497
	Effect of dilutive securities:
	Stock options and restricted stock units			912			971			963			949
	Diluted weighted average common shares outstanding			117,163			120,578			117,803			121,446
	Earnings per basic common share from continuing operations		$	0.44		$	0.42		$	1.33		$	1.32
	Earnings per basic common share from discontinued operations			—			0.04			0.72			0.13
	Earnings per basic common share		$	0.44		$	0.46		$	2.05		$	1.45
	Earnings per diluted common share from continuing operations		$	0.44		$	0.42		$	1.32		$	1.31
	Earnings per diluted common share from discontinued operations			—			0.04			0.71			0.13
	Earnings per diluted common share		$	0.44		$	0.46		$	2.03		$	1.44
	(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.

Property_Equipment_and_Leaseho

Property, Equipment and Leasehold Improvements	9 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Abstract]	'
Property, Equipment and Leasehold Improvements	'
	6. PROPERTY, EQUIPMENT AND LEASEHOLD IMPROVEMENTS
	Property, equipment and leasehold improvements at September 30, 2014 and December 31, 2013 consisted of the following:
			As of
	Type		September 30,			December 31,
			2014(1)			2013
			(in thousands)
	Computer & related equipment		$	112,185		$	86,384
	Furniture & fixtures			9,734			9,108
	Leasehold improvements			54,277			52,776
	Work-in-process			10,602			12,691
	Subtotal			186,798			160,959
	Accumulated depreciation and amortization			(93,011	)		(75,371	)
	Property, equipment and leasehold improvements, net		$	93,787		$	85,588
	(1)	Property, equipment and leasehold improvements as of September 30, 2014 reflects the disposition and addition of property, equipment and leasehold improvements associated with the sale of ISS and acquisition of Governance Holdings Co. (“GMI Ratings”), respectively. See Note 3, “Dispositions and Discontinued Operations,” and Note 11, “Acquisitions,” for additional information.
	Depreciation and amortization expense of property, equipment and leasehold improvements was $6.3 million and $5.4 million for the three months ended September 30, 2014 and 2013, respectively. Depreciation and amortization expense of property, equipment and leasehold improvements was $18.1 million and $14.8 million for the nine months ended September 30, 2014 and 2013, respectively.

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill and Intangible Assets	'
	7. GOODWILL AND INTANGIBLE ASSETS
	Goodwill
	The Company carries goodwill reflected in the table below:
			Goodwill
	(in thousands)
	Goodwill at December 31, 2013		$	1,813,164
	Changes to goodwill(1)			(244,288	)
	Foreign exchange translation adjustment			(1,433	)
	Goodwill at September 30, 2014		$	1,567,443
	(1)	Changes to goodwill reflect the disposition and addition of goodwill associated with the sale of ISS and acquisition of GMI Ratings, respectively. See Note 3, “Dispositions and Discontinued Operations,” and Note 11, “Acquisitions,” for additional information.
	Intangible Assets
	Amortization expense related to intangible assets for the three months ended September 30, 2014 and 2013 was $11.6 million and $11.2 million, respectively. Amortization expense related to intangible assets for the nine months ended September 30, 2014 and 2013 was $34.3 million and $33.6 million, respectively.
	The gross carrying amounts and accumulated amortization totals related to the Company’s identifiable intangible assets are as follows:
			As of
	(in thousands)		September 30,			December 31,
			2014(1)			2013
	Gross intangible assets:
	Customer relationships		$	360,835		$	478,735
	Trademarks/trade names			223,382			257,282
	Technology/software			191,540			199,778
	Proprietary process			—			3,800
	Proprietary data			28,627			28,527
	Covenants not to compete			900			—
	Subtotal			805,284			968,122
	Foreign exchange translation adjustment			677			1,962
	Total gross intangible assets		$	805,961		$	970,084
	Accumulated amortization:
	Customer relationships		$	(112,986	)	$	(125,359	)
	Trademarks/trade names			(78,548	)		(75,696	)
	Technology/software			(165,220	)		(168,481	)
	Proprietary process			—			(2,269	)
	Proprietary data			(4,043	)		(2,326	)
	Covenants not to compete			(75	)		—
	Subtotal			(360,872	)		(374,131	)
	Foreign exchange translation adjustment			(55	)		(246	)
	Total accumulated amortization		$	(360,927	)	$	(374,377	)
	Net intangible assets:
	Customer relationships		$	247,849		$	353,376
	Trademarks/trade names			144,834			181,586
	Technology/software			26,320			31,297
	Proprietary process			—			1,531
	Proprietary data			24,584			26,201
	Covenants not to compete			825			—
	Subtotal			444,412			593,991
	Foreign exchange translation adjustment			622			1,716
	Total net intangible assets		$	445,034		$	595,707
	(1)	Intangible assets and the associated accumulated amortization as of September 30, 2014 reflect the disposition and addition of intangible assets associated with the sale of ISS and acquisition of GMI Ratings, respectively. See Note 3, “Dispositions and Discontinued Operations,” and Note 11, “Acquisitions,” for additional information.
	The estimated amortization expense for the remainder of 2014 and succeeding years is presented below:
	Fiscal Year		Amortization Expense
			(in thousands)
	Remainder 2014		$	11,647
	2015			46,929
	2016			46,413
	2017			41,186
	2018			38,436
	Thereafter			260,423
	Total		$	445,034

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2014
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, 2014 and 2013 was $6.3 million and $6.1 million, respectively. Rent expense for the nine months ended September 30, 2014 and 2013 was $19.7 million and $17.6 million, respectively.
	Return of capital. 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”).
	On December 13, 2012, as part of the 2012 Repurchase Program, the Company entered into its first accelerated share repurchase (“ASR”) agreement to initiate a repurchase aggregating $100.0 million (the “December 2012 ASR Program”). As a result of the December 2012 ASR Program, the Company received 2.2 million shares on December 14, 2012 and 0.8 million shares on July 31, 2013 for a combined average purchase price of $33.47 per share.
	On August 1, 2013, MSCI entered into a second ASR agreement to initiate share repurchases aggregating $100.0 million (the “August 2013 ASR Program”). As a result of the August 2013 ASR Program, the Company received 1.9 million shares on August 2, 2013 and 0.5 million shares on December 30, 2013 for a combined average purchase price of $41.06 per share.
	On February 6, 2014, MSCI utilized the remaining repurchase authorization provided by the 2012 Repurchase Program by entering into a third ASR agreement to initiate share repurchases aggregating $100.0 million (the “February 2014 ASR Program”). As a result of the February 2014 ASR Program, the Company received 1.7 million shares on February 7, 2014 and 0.6 million shares on May 5, 2014 for a combined average purchase price of $43.10 per share.
	On February 4, 2014, 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 which will be available from time to time at management’s discretion (the “2014 Repurchase Program”). On September 17, 2014, the Board of Directors increased the approval under the 2014 Repurchase Program from $300.0 million to $850.0 million. Share repurchases made pursuant to the authority remaining under the 2014 Repurchase Program may take place through December 31, 2016 in the open market or in privately negotiated transactions from time to time based on market and other conditions. This authorization may be modified, suspended, terminated or extended by the Board of Directors at any time without prior notice.
	On September 18, 2014, as part of the 2014 Repurchase Program, the Company entered into a fourth ASR agreement to initiate share repurchases aggregating $300.0 million (the “September 2014 ASR Program”). As a result of the September 2014 ASR Program, on September 19, 2014, the Company paid $300.0 million in cash and received approximately 4.5 million shares of MSCI’s common stock. The Company may also receive additional shares at or prior to maturity of the ASR Agreement in May 2015.
	The $300.0 million payment for the September 2014 ASR Program was initially split and recorded as a $210.0 million increase to “Treasury stock” and a $90.0 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.
	On September 17, 2014, the Board of Directors approved a plan to initiate a regular quarterly cash dividend. Accordingly, the Board of Directors declared the Company’s first regular quarterly dividend of $0.18 per share of common stock that will be paid on October 31, 2014 to shareholders of record as of the close of trading on October 15, 2014. The Company expects the initial annual dividend rate to be $0.72 per share. As of September 30, 2014, the Company accrued for the declared cash dividend of $20.4 million in “Other accrued liabilities” on the Company’s Unaudited Condensed Consolidated Statement of Financial Condition which will be paid on October 31, 2014.
	Long-term debt. On June 1, 2010, the Company entered into a senior secured credit facility (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. 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 provided 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 Amended and Restated Credit Facility also amended certain negative covenants, including financial covenants.
	In March 2013, the Company made a $15.0 million prepayment on the 2012 Term Loan.
	On December 12, 2013, the Company entered into an agreement that extended the maturity of the Amended and Restated Credit Facility from May 2017 to December 2018 (the “New Amended and Restated Credit Facility”). The Company also amended the amortization schedule of required debt payments under the 2012 Term Loan. Pursuant to the New Amended and Restated Credit Facility, the Company is required to repay $5.1 million in quarterly payments over the first two years and $10.1 million in quarterly payments over the following three years, with the exception of the final payment in December 2018, which will be $658.1 million (assuming no further prepayments). As of September 30, 2014, no such prepayments have been made.
	The 2012 Term Loan bears interest equal to LIBOR plus a margin. As of September 30, 2014, the 2012 Term Loan bore interest at LIBOR plus a margin of 2.25%, or 2.40%.
	Current maturities of long-term debt at September 30, 2014 were $19.8 million, net of a $0.5 million discount. Long-term debt, net of current maturities at September 30, 2014 was $773.2 million, net of a $1.4 million discount.
	Current maturities of long-term debt at December 31, 2013 were $19.8 million, net of a $0.5 million discount. Long-term debt, net of current maturities at December 31, 2013 was $788.0 million, net of a $1.7 million discount.
	In connection with entering into the New Amended and Restated Credit Facility, certain fees were paid and are being amortized over the life of the New Amended and Restated Credit Facility. At September 30, 2014, $7.0 million of the deferred financing fees remain unamortized, $1.7 million of which is included in “Prepaid and other assets” and $5.3 million of which is included in “Other non-current assets” on the Company’s Unaudited Condensed Consolidated Statement of Financial Condition.
	The Company amortized $0.4 million and $0.7 million of deferred financing fees in interest expense during the three months ended September 30, 2014 and 2013, respectively. The Company amortized $1.3 million and $2.2 million of deferred financing fees in interest expense during the nine months ended September 30, 2014 and 2013, respectively. Approximately $0.1 million and $0.2 million of debt discount was amortized in interest expense during the three months ended September 30, 2014 and 2013, respectively. Approximately $0.4 million and $0.7 million of debt discount were amortized in interest expense during the nine months ended September 30, 2014 and 2013, respectively.
	At September 30, 2014 and December 31, 2013, the fair market value of the Company’s debt obligations was $782.9 million and $812.0 million, respectively. The fair market value is determined in accordance with accounting standards related to the determination of fair value 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.
	As of September 30, 2014, the Company’s retained earnings of $978.4 million were restricted as to the payments of dividends. As outlined in the New 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, 2014, the amount available for restricted payments was $161.6 million, after taking into account dividends declared, reflecting the Company’s cumulative retained excess cash flows (“CRECF”), as defined in the New Amended and Restated Credit Facility, through December 31, 2013 and adjusted for, among other things, any restricted payments made during the nine months ended September 30, 2014. To the extent the CRECF is utilized for other actions restricted under the New 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.
	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.
	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, 2014, the Company had one outstanding foreign currency forward with a notional amount of $12.0 million that was not designated as a hedge in a qualifying hedging relationship.
	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)	Location in the Unaudited	As of			As of
		Condensed	September 30, 2014			December 31, 2013
		Consolidated Statements of
		Financial Condition
	Non-designated hedging instruments:
	Liability derivatives:
	Foreign exchange contracts	Other accrued liabilities	$	-236		$	-156
	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.
	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 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,
			2014			2013
	Foreign exchange contracts	Other expense	$	(258	)	$	(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,
			2014			2013
	Foreign exchange contracts	Other expense	$	(825	)	$	(185	)

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	9. INCOME TAXES
	The Company’s provision for income taxes was $81.9 million and $76.8 million for the nine months ended September 30, 2014 and 2013, respectively. These amounts reflect effective tax rates of 34.5% and 32.6% for the nine months ended September 30, 2014 and 2013, respectively.
	The effective tax rate of 34.5% for the nine months ended September 30, 2014 reflects the Company’s estimate of the effective tax rate for the period and is impacted by certain discrete items totaling $3.4 million related to state taxes, the release of reserves associated with certain IRS examinations and certain federal and foreign discrete items related to the filing of related tax returns, the effect of which was to decrease the Company’s effective tax rate by 1.4 percentage points. The effective tax rate of 32.6% 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 $3.5 million, the effect of which was to decrease the Company’s effective tax rate by 1.5 percentage points.
	The Company is under examination by the Internal Revenue Service and other tax authorities in certain jurisdictions, including foreign jurisdictions, such as the United Kingdom, and states in which the Company has significant business operations, such as New York. The tax years currently under examination vary by jurisdiction but include years ranging from 2005 through 2013. As a result of having previously been a member of the Morgan Stanley consolidated group, the Company may have future settlements with Morgan Stanley related to the ultimate disposition of their New York State and New York City examination relating to the tax years 2007 through 2008 and their IRS examination relating to the tax years 2006 through 2008. The Company does not believe it has any material exposure to the New York State and New York City examination. 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.

Segment_Information

Segment Information	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
Segment Information	'
	10. 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 and in assessing performance. 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 operated as two segments in the year ended December 31, 2013, the Performance and Risk business and the Governance business. These designations were made as the discrete operating results of these segments were reviewed by the Company’s CODM for purposes of making operating decisions and assessing financial performance.
	On March 17, 2014, MSCI entered into a definitive agreement to sell ISS, which, together with the previously disposed of CFRA product line, made up the Company’s Governance segment and are now reflected in “Income from discontinued operations, net of income taxes” in the Unaudited Condensed Consolidated Statements of Income. The Company completed the sale of ISS on April 30, 2014. As a result, the Company now operates and reports as a single business segment (see Note 3, “Dispositions and Discontinued Operations,” for further details).
	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,
			2014		2013		2014		2013
			(in thousands)
	Revenues
	Americas:
	United States		$	118,721	$	104,917	$	347,779	$	308,341
	Other			9,171		8,993		27,961		24,529
	Total Americas			127,892		113,910		375,740		332,870
	EMEA:
	United Kingdom			40,104		35,758		115,961		103,485
	Other			52,067		49,418		160,695		152,826
	Total EMEA			92,171		85,176		276,656		256,311
	Asia & Australia:
	Japan			11,573		11,919		35,385		35,156
	Other			20,025		17,603		57,794		52,163
	Total Asia & Australia			31,598		29,522		93,179		87,319
	Total		$	251,661	$	228,608	$	745,575	$	676,500
	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,
			2014(1)		2013
			(in thousands)
	Long-lived assets
	Americas:
	United States		$	1,953,113	$	2,338,124
	Other			3,719		4,082
	Total Americas			1,956,832		2,342,206
	EMEA:
	United Kingdom			126,749		133,411
	Other			11,933		11,871
	Total EMEA			138,682		145,282
	Asia & Australia:
	Japan			987		1,543
	Other			9,763		5,428
	Total Asia & Australia			10,750		6,971
	Total		$	2,106,264	$	2,494,459
	-1	Long-lived assets as of September 30, 2014 reflect the disposition and addition of long-lived assets with the sale of ISS and acquisition of GMI Ratings, respectively. See Note 3, “Dispositions and Discontinued Operations,” and Note 11, “Acquisitions,” for additional information.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
Acquisitions	'
	11. ACQUISITIONS
	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 GMI Ratings
	On August 11, 2014, the Company completed the acquisition of GMI Ratings for $15.5 million through its subsidiary MSCI ESG Research Inc., subject to final working capital adjustments. GMI Ratings is a provider of corporate governance research and ratings on over 6,000 companies worldwide. Clients of GMI Ratings include leading institutional investors, banks, insurers, auditors, regulators and corporations seeking to incorporate ESG factors into risk assessment and decision-making.
	As of September 30, 2014, the preliminary purchase price allocations for the GMI Ratings acquisition were $9.9 million for goodwill, $3.6 million for identifiable intangible assets, $8.1 million for assets other than identifiable intangible assets and $6.1 million for other liabilities.

Introduction_and_Basis_of_Pres1

Introduction and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Basis of Presentation and Use of Estimates	'
	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, 2014 and December 31, 2013, the results of operations and comprehensive income for the three and nine months ended September 30, 2014 and 2013 and cash flows for the nine months ended September 30, 2014 and 2013. 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, 2013. The unaudited condensed consolidated financial statement information as of December 31, 2013 has been derived from the 2013 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. Certain prior period amounts have been reclassified to conform to the current year financial statement presentation.
Revision	'
	Revision
	In connection with the preparation of the Company’s unaudited condensed consolidated financial statements for the three months ended June 30, 2014, the Company determined that it had understated its net tax liabilities in certain years prior to December 31, 2012. As a result of these errors, the Company has recorded the following corrections as of December 31, 2013: (i) an $11.3 million decrease to beginning retained earnings, (ii) a $0.7 million decrease to additional paid in capital, (iii) a $12.8 million decrease to prepaid taxes, (iv) a $13.6 million increase to long-term deferred tax liabilities and (v) a $14.3 million increase to goodwill. In accordance with the accounting guidance found in Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Subtopic 250-10, “Accounting Changes and Error Corrections,” the Company has revised its Unaudited Condensed Consolidated Statements of Financial Condition as of December 31, 2013 to reflect these corrections. The Company will revise all other previously reported results as such financial information is included in future filings.
	In accordance with SEC Staff Accounting Bulletin No. 99, “Materiality,” the Company assessed the materiality of the adjustments and concluded that these corrections were not material to any of its previously issued financial statements. The Company also concluded that its compliance with debt covenants would not have been affected by these adjustments.
	Accordingly, the Company has revised the Unaudited Condensed Consolidated Statement of Financial Condition as of December 31, 2013 from amounts previously reported as follows:
		(in thousands)
		As Previously		Adjustment			As Revised
		Reported
	Prepaid taxes	$	27,333	$	(12,765	)	$	14,568
	Total current assets	$	637,035	$	(12,765	)	$	624,270
	Goodwill	$	1,798,821	$	14,343		$	1,813,164
	Total assets	$	3,134,537	$	1,578		$	3,136,115
	Deferred taxes	$	221,054	$	13,595		$	234,649
	Total liabilities	$	1,558,173	$	13,595		$	1,571,768
	Additional paid in capital	$	1,073,893	$	(736	)	$	1,073,157
	Retained earnings	$	770,256	$	(11,281	)	$	758,975
	Total shareholders’ equity	$	1,576,364	$	(12,017	)	$	1,564,347
	Total liabilities and shareholders’ equity	$	3,134,537	$	1,578		$	3,136,115
Concentrations	'
	Concentrations
	Financial instruments that may potentially subject the Company to concentration risk consist principally of cash deposits. At September 30, 2014 and December 31, 2013, cash and cash equivalent amounts were $448.2 million and $358.4 million, respectively. The Company receives interest at prevailing money market fund rates on its cash deposits.
	For the nine months ended September 30, 2014, BlackRock, Inc. accounted for 10.6% of the Company’s operating revenues. For the nine months ended September 30, 2013, no single customer accounted for 10.0% or more of the Company’s operating revenues.

Introduction_and_Basis_of_Pres2

Introduction and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Schedule of Revised Condensed Consolidated Financial Statements Amounts Previously Reported	'
	Accordingly, the Company has revised the Unaudited Condensed Consolidated Statement of Financial Condition as of December 31, 2013 from amounts previously reported as follows:
		(in thousands)
		As Previously		Adjustment			As Revised
		Reported
	Prepaid taxes	$	27,333	$	(12,765	)	$	14,568
	Total current assets	$	637,035	$	(12,765	)	$	624,270
	Goodwill	$	1,798,821	$	14,343		$	1,813,164
	Total assets	$	3,134,537	$	1,578		$	3,136,115
	Deferred taxes	$	221,054	$	13,595		$	234,649
	Total liabilities	$	1,558,173	$	13,595		$	1,571,768
	Additional paid in capital	$	1,073,893	$	(736	)	$	1,073,157
	Retained earnings	$	770,256	$	(11,281	)	$	758,975
	Total shareholders’ equity	$	1,576,364	$	(12,017	)	$	1,564,347
	Total liabilities and shareholders’ equity	$	3,134,537	$	1,578		$	3,136,115

Dispositions_and_Discontinued_1

Dispositions and Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]	'
Schedule of Value of Assets and Liabilities Disposed	'
	The value of the assets and liabilities of ISS that were disposed, directly attributable transaction costs and the resulting gain on disposal that has been reported in “Income from discontinued operations, net of income taxes” for the three and nine months ended September 30, 2014 are as follows:
	(in thousands)
	Cash proceeds	$	367,355
	Less: Working capital adjustments		(311	)
	Total proceeds		367,044
	Less assets sold and liabilities relieved resulting from disposal:
	Cash and cash equivalents		(4,544	)
	Accounts receivable		(15,765	)
	Deferred taxes (current)		(3,174	)
	Prepaid taxes		(617	)
	Prepaid and other assets		(4,500	)
	Property, equipment and leasehold improvements (net of accumulated depreciation and amortization of $4,213)		(8,544	)
	Goodwill		(254,233	)
	Intangible assets (net of accumulated amortization of $50,283)		(121,269	)
	Other non-current assets		(1,645	)
	Accounts payable		574
	Accrued compensation and related benefits		6,783
	Other accrued liabilities		4,034
	Deferred revenue		51,767
	Deferred taxes (non-current)		59,129
	Other non-current liabilities		5,576
	Other comprehensive income including currency translation adjustments and pension and other post-retirement adjustments		4,004
	Net assets sold		(282,424	)
	Less: Transaction costs		(5,946	)
	Gain on sale of ISS	$	78,674
Schedule of Income (Loss) Amounts Associated with Discontinued Operations	'
	Income (loss) from discontinued operations. Amounts associated with discontinued operations reflected in the Unaudited Condensed Consolidated Statements of Income for the three months ended September 30, 2014 and 2013 are as follows:
		Three Months Ended
		September 30,
		2014			2013
		(in thousands)
	Revenue from discontinued operations	$	—		$	29,630
	Income (loss) from discontinued operations before provision (benefit) for income taxes	$	(110	)	$	8,507
	Provision (benefit) for income taxes		(100	)		3,133
	Income (loss) from discontinued operations, net of income taxes	$	(10	)	$	5,374
	Amounts associated with discontinued operations reflected in the Unaudited Condensed Consolidated Statements of Income for the nine months ended September 30, 2014 and 2013 are as follows:
		Nine Months Ended
		September 30,
		2014			2013
		(in thousands)
	Revenue from discontinued operations	$	43,122		$	91,545
	Income from discontinued operations before provision for income taxes	$	86,254		$	25,223
	Provision for income taxes		2,154			8,958
	Income from discontinued operations, net of income taxes	$	84,100		$	16,265

Reclassifications_out_of_Accum1

Reclassifications out of Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]	'
Schedule of Reclassifications out of Accumulated Other Comprehensive Income (Loss)	'
	Reclassifications Out of Accumulated Other Comprehensive Income (Loss)(1)
	(in thousands)
	Details about Accumulated Other		Amount Reclassified from Accumulated Other						Affected Line Item in the
	Comprehensive Income (Loss)		Comprehensive Income (Loss)						Unaudited Condensed
	Components								Consolidated Statements of
									Income
			Three Months Ended			Three Months Ended
			September 30,			September 30,
			2014			2013
	Unrealized losses on cash flow hedges Interest rate contracts		$	—		$	(197	)	Interest expense
				—			77		Tax benefit
			$	—		$	(120	)	Net of tax
	Unrealized gains on available-for-sale securities
	Short-term investments		$	—		$	—		Interest income
				—			—		Tax expense
			$	—		$	—		Net of tax
	Defined benefit pension plans
	Amount recognized as a component of net periodic benefit expense for curtailments and settlements		$	—		$	—		-2
				—			—		Tax expense
			$	—		$	—		Net of tax
	Foreign currency translation adjustment		$	—		$	—		-2
	Total reclassifications for the period, net of tax		$	—		$	(120	)
	(1)	Amounts in parentheses indicate expenses or losses moved to the Unaudited Condensed Consolidated Statements of Income.
	(2)	These accumulated other comprehensive income components were reclassified to “Income from discontinued operations, net of taxes” as part of the gain on the disposition of ISS.
	Reclassifications Out of Accumulated Other Comprehensive Income (Loss)(1)
	(in thousands)
	Details about Accumulated Other		Amount Reclassified from Accumulated Other						Affected Line Item in the
	Comprehensive Income (Loss)		Comprehensive Income (Loss)						Unaudited Condensed
	Components								Consolidated Statements of
									Income
			Nine Months Ended			Nine Months Ended
			September 30,			September 30,
			2014			2013
	Unrealized losses on cash flow hedges Interest rate contracts		$	—		$	(1,364	)	Interest expense
				—			524		Tax benefit
			$	—		$	(840	)	Net of tax
	Unrealized gains on available-for-sale securities
	Short-term investments		$	—		$	5		Interest income
				—			(2	)	Tax expense
			$	—		$	3		Net of tax
	Defined benefit pension plans
	Amount recognized as a component of net periodic benefit expense for curtailments and settlements		$	(186	)	$	—		-2
				6			—		Tax expense
			$	(180	)	$	—		Net of tax
	Foreign currency translation adjustment		$	4,184		$	—		-2
	Total reclassifications for the period, net of tax		$	4,004		$	(837	)
	(1)	Amounts in parentheses indicate expenses or losses moved to the Unaudited Condensed Consolidated Statements of Income.
	(2)	These accumulated other comprehensive income components were reclassified to “Income from discontinued operations, net of taxes” as part of the gain on the disposition of ISS.

Earnings_Per_Common_Share_Tabl

Earnings Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2014
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,
			2014			2013			2014			2013
	(in thousands, except per share data)
	Income from continuing operations, net of income taxes		$	51,724		$	49,936		$	155,673		$	159,035
	Income (loss) from discontinued operations, net of income taxes			(10	)		5,374			84,100			16,265
	Net income		$	51,714		$	55,310		$	239,773		$	175,300
	Less: Allocations of earnings to unvested restricted stock units (1)			(69	)		(211	)		(320	)		(668	)
	Earnings available to MSCI common shareholders		$	51,645		$	55,099		$	239,453		$	174,632
	Basic weighted average common shares outstanding			116,251			119,607			116,840			120,497
	Effect of dilutive securities:
	Stock options and restricted stock units			912			971			963			949
	Diluted weighted average common shares outstanding			117,163			120,578			117,803			121,446
	Earnings per basic common share from continuing operations		$	0.44		$	0.42		$	1.33		$	1.32
	Earnings per basic common share from discontinued operations			—			0.04			0.72			0.13
	Earnings per basic common share		$	0.44		$	0.46		$	2.05		$	1.45
	Earnings per diluted common share from continuing operations		$	0.44		$	0.42		$	1.32		$	1.31
	Earnings per diluted common share from discontinued operations			—			0.04			0.71			0.13
	Earnings per diluted common share		$	0.44		$	0.46		$	2.03		$	1.44
	(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.

Property_Equipment_and_Leaseho1

Property, Equipment and Leasehold Improvements (Tables)	9 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Abstract]	'
Schedule of Property, Equipment and Leasehold Improvements	'
	Property, equipment and leasehold improvements at September 30, 2014 and December 31, 2013 consisted of the following:
			As of
	Type		September 30,			December 31,
			2014(1)			2013
			(in thousands)
	Computer & related equipment		$	112,185		$	86,384
	Furniture & fixtures			9,734			9,108
	Leasehold improvements			54,277			52,776
	Work-in-process			10,602			12,691
	Subtotal			186,798			160,959
	Accumulated depreciation and amortization			(93,011	)		(75,371	)
	Property, equipment and leasehold improvements, net		$	93,787		$	85,588
	(1)	Property, equipment and leasehold improvements as of September 30, 2014 reflects the disposition and addition of property, equipment and leasehold improvements associated with the sale of ISS and acquisition of Governance Holdings Co. (“GMI Ratings”), respectively. See Note 3, “Dispositions and Discontinued Operations,” and Note 11, “Acquisitions,” for additional information.

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Schedule of Goodwill	'
	The Company carries goodwill reflected in the table below:
			Goodwill
	(in thousands)
	Goodwill at December 31, 2013		$	1,813,164
	Changes to goodwill(1)			(244,288	)
	Foreign exchange translation adjustment			(1,433	)
	Goodwill at September 30, 2014		$	1,567,443
	(1)	Changes to goodwill reflect the disposition and addition of goodwill associated with the sale of ISS and acquisition of GMI Ratings, respectively. See Note 3, “Dispositions and Discontinued Operations,” and Note 11, “Acquisitions,” for additional information.
Components of Intangible Assets by Major Class	'
	The gross carrying amounts and accumulated amortization totals related to the Company’s identifiable intangible assets are as follows:
			As of
	(in thousands)		September 30,			December 31,
			2014(1)			2013
	Gross intangible assets:
	Customer relationships		$	360,835		$	478,735
	Trademarks/trade names			223,382			257,282
	Technology/software			191,540			199,778
	Proprietary process			—			3,800
	Proprietary data			28,627			28,527
	Covenants not to compete			900			—
	Subtotal			805,284			968,122
	Foreign exchange translation adjustment			677			1,962
	Total gross intangible assets		$	805,961		$	970,084
	Accumulated amortization:
	Customer relationships		$	(112,986	)	$	(125,359	)
	Trademarks/trade names			(78,548	)		(75,696	)
	Technology/software			(165,220	)		(168,481	)
	Proprietary process			—			(2,269	)
	Proprietary data			(4,043	)		(2,326	)
	Covenants not to compete			(75	)		—
	Subtotal			(360,872	)		(374,131	)
	Foreign exchange translation adjustment			(55	)		(246	)
	Total accumulated amortization		$	(360,927	)	$	(374,377	)
	Net intangible assets:
	Customer relationships		$	247,849		$	353,376
	Trademarks/trade names			144,834			181,586
	Technology/software			26,320			31,297
	Proprietary process			—			1,531
	Proprietary data			24,584			26,201
	Covenants not to compete			825			—
	Subtotal			444,412			593,991
	Foreign exchange translation adjustment			622			1,716
	Total net intangible assets		$	445,034		$	595,707
	(1)	Intangible assets and the associated accumulated amortization as of September 30, 2014 reflect the disposition and addition of intangible assets associated with the sale of ISS and acquisition of GMI Ratings, respectively. See Note 3, “Dispositions and Discontinued Operations,” and Note 11, “Acquisitions,” for additional information.
Estimated Amortization Expense for Remainder of 2014 and Succeeding Years	'
	The estimated amortization expense for the remainder of 2014 and succeeding years is presented below:
	Fiscal Year		Amortization Expense
			(in thousands)
	Remainder 2014		$	11,647
	2015			46,929
	2016			46,413
	2017			41,186
	2018			38,436
	Thereafter			260,423
	Total		$	445,034

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2014
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)	Location in the Unaudited	As of			As of
		Condensed	September 30, 2014			December 31, 2013
		Consolidated Statements of
		Financial Condition
	Non-designated hedging instruments:
	Liability derivatives:
	Foreign exchange contracts	Other accrued liabilities	$	-236		$	-156
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 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,
			2014			2013
	Foreign exchange contracts	Other expense	$	(258	)	$	(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,
			2014			2013
	Foreign exchange contracts	Other expense	$	(825	)	$	(185	)

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
Revenue by Geographic Area	'
	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,
			2014		2013		2014		2013
			(in thousands)
	Revenues
	Americas:
	United States		$	118,721	$	104,917	$	347,779	$	308,341
	Other			9,171		8,993		27,961		24,529
	Total Americas			127,892		113,910		375,740		332,870
	EMEA:
	United Kingdom			40,104		35,758		115,961		103,485
	Other			52,067		49,418		160,695		152,826
	Total EMEA			92,171		85,176		276,656		256,311
	Asia & Australia:
	Japan			11,573		11,919		35,385		35,156
	Other			20,025		17,603		57,794		52,163
	Total Asia & Australia			31,598		29,522		93,179		87,319
	Total		$	251,661	$	228,608	$	745,575	$	676,500
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,
			2014(1)		2013
			(in thousands)
	Long-lived assets
	Americas:
	United States		$	1,953,113	$	2,338,124
	Other			3,719		4,082
	Total Americas			1,956,832		2,342,206
	EMEA:
	United Kingdom			126,749		133,411
	Other			11,933		11,871
	Total EMEA			138,682		145,282
	Asia & Australia:
	Japan			987		1,543
	Other			9,763		5,428
	Total Asia & Australia			10,750		6,971
	Total		$	2,106,264	$	2,494,459
	-1	Long-lived assets as of September 30, 2014 reflect the disposition and addition of long-lived assets with the sale of ISS and acquisition of GMI Ratings, respectively. See Note 3, “Dispositions and Discontinued Operations,” and Note 11, “Acquisitions,” for additional information.

Introduction_and_Basis_of_Pres3

Introduction and Basis of Presentation - Additional Information (Detail) (USD $)	0 Months Ended	9 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Mar. 17, 2014	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
	Segment			Segment
Introduction And Basis Of Presentation [Line Items]	'	'	'	'	'
Number of operating segments	1	'	'	2	'
Decrease to beginning retained earnings	'	$978,358	'	$758,975	'
Decrease to additional paid in capital	'	1,017,305	'	1,073,157	'
Decrease to prepaid taxes	'	35,027	'	14,568	'
Increase to long-term deferred tax liabilities	'	171,681	'	234,649	'
Increase to goodwill	'	1,567,443	'	1,813,164	'
Cash and cash equivalents	'	448,193	283,750	358,434	183,309
Percentage of operating revenues accounted for by major customer	'	10.60%	10.00%	'	'
Institutional Shareholder Services Inc. [Member]	'	'	'	'	'
Introduction And Basis Of Presentation [Line Items]	'	'	'	'	'
Sale completion date	'	30-Apr-14	'	'	'
Adjustment [Member]	'	'	'	'	'
Introduction And Basis Of Presentation [Line Items]	'	'	'	'	'
Decrease to beginning retained earnings	'	'	'	-11,281	'
Decrease to additional paid in capital	'	'	'	-736	'
Decrease to prepaid taxes	'	'	'	-12,765	'
Increase to long-term deferred tax liabilities	'	'	'	13,595	'
Increase to goodwill	'	'	'	$14,343	'

Introduction_and_Basis_of_Pres4

Introduction and Basis of Presentation - Schedule of Revised Condensed Consolidated Financial Statements Amounts Previously Reported (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Prepaid taxes	$35,027	$14,568
Total current assets	758,589	624,270
Goodwill	1,567,443	1,813,164
Total assets	2,880,279	3,136,115
Deferred taxes	171,681	234,649
Total liabilities	1,483,745	1,571,768
Additional paid in capital	1,017,305	1,073,157
Retained earnings	978,358	758,975
Total shareholders' equity	1,396,534	1,564,347
Total liabilities and shareholders' equity	2,880,279	3,136,115
As Previously Reported [Member]	'	'
Prepaid taxes	'	27,333
Total current assets	'	637,035
Goodwill	'	1,798,821
Total assets	'	3,134,537
Deferred taxes	'	221,054
Total liabilities	'	1,558,173
Additional paid in capital	'	1,073,893
Retained earnings	'	770,256
Total shareholders' equity	'	1,576,364
Total liabilities and shareholders' equity	'	3,134,537
Adjustment [Member]	'	'
Prepaid taxes	'	-12,765
Total current assets	'	-12,765
Goodwill	'	14,343
Total assets	'	1,578
Deferred taxes	'	13,595
Total liabilities	'	13,595
Additional paid in capital	'	-736
Retained earnings	'	-11,281
Total shareholders' equity	'	-12,017
Total liabilities and shareholders' equity	'	$1,578

Dispositions_and_Discontinued_2

Dispositions and Discontinued Operations - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended	9 Months Ended
	Apr. 30, 2014	Mar. 31, 2014	Sep. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]	'	'	'
Definitive sale agreement date	'	'	'2014-03-17
Sale proceeds from divestiture	$367,400,000	'	$367,355,000
Income tax benefit	'	$30,600,000	'

Dispositions_and_Discontinued_3

Dispositions and Discontinued Operations - Schedule of Value of Assets and Liabilities Disposed (Detail) (USD $)	0 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Apr. 30, 2014	Sep. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]	'	'
Cash proceeds	$367,400	$367,355
Less: Working capital adjustments	'	-311
Total proceeds	'	367,044
Less assets sold and liabilities relieved resulting from disposal:	'	'
Cash and cash equivalents	'	-4,544
Accounts receivable	'	-15,765
Deferred taxes (current)	'	-3,174
Prepaid taxes	'	-617
Prepaid and other assets	'	-4,500
Property, equipment and leasehold improvements (net of accumulated depreciation and amortization of $4,213)	'	-8,544
Goodwill	'	-254,233
Intangible assets (net of accumulated amortization of $50,283)	'	-121,269
Other non-current assets	'	-1,645
Accounts payable	'	574
Accrued compensation and related benefits	'	6,783
Other accrued liabilities	'	4,034
Deferred revenue	'	51,767
Deferred taxes (non-current)	'	59,129
Other non-current liabilities	'	5,576
Other comprehensive income including currency translation adjustments and pension and other post-retirement adjustments	'	4,004
Net assets sold	'	-282,424
Less: Transaction costs	'	-5,946
Gain on sale of ISS	'	$78,674

Dispositions_and_Discontinued_4

Dispositions and Discontinued Operations - Schedule of Value of Assets and Liabilities Disposed (Parenthetical) (Detail) (USD $)	Sep. 30, 2014
In Thousands, unless otherwise specified
Discontinued Operations and Disposal Groups [Abstract]	'
Property, equipment and leasehold improvements, accumulated depreciation and amortization	$4,213
Intangible assets, accumulated amortization	$50,283

Dispositions_and_Discontinued_5

Dispositions and Discontinued Operations - Schedule of Income (Loss) Amounts Associated with Discontinued Operations (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Discontinued Operations and Disposal Groups [Abstract]	'	'	'	'
Revenue from discontinued operations	'	$29,630	$43,122	$91,545
Income (loss) from discontinued operations before provision (benefit) for income taxes	-110	8,507	86,254	25,223
Provision (benefit) for income taxes	-100	3,133	2,154	8,958
Income (loss) from discontinued operations, net of income taxes	($10)	$5,374	$84,100	$16,265

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, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Interest expense	($5,604)	($5,828)	($16,029)	($19,343)
Interest income	277	227	625	650
Tax benefit (expense)	-28,272	-27,804	-81,937	-76,799
Net income	51,714	55,310	239,773	175,300
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) [Member]	'	'	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Foreign currency translation adjustment	'	'	4,184	'
Net income	'	-120	4,004	-837
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) [Member] | Unrealized Losses on Cash Flow Hedges [Member] | Interest Rate Contracts [Member]	'	'	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Interest expense	'	-197	'	-1,364
Tax benefit (expense)	'	77	'	524
Net income	'	-120	'	-840
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
Tax benefit (expense)	'	'	'	-2
Net income	'	'	'	3
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) [Member] | Defined Benefit Pension Plans Amount Recognized as a Component of Net Periodic Benefit Expense [Member] | Curtailments and Settlements [Member]	'	'	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Net periodic benefit expense	'	'	-186	'
Tax benefit (expense)	'	'	6	'
Net income	'	'	($180)	'

Earnings_Per_Common_Share_Addi

Earnings Per Common Share - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Anti-dilutive securities excluded from the calculation of diluted EPS	104,494	1,133	104,346	453

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, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Income from continuing operations, net of income taxes	$51,724	$49,936	$155,673	$159,035
Income (loss) from discontinued operations, net of income taxes	-10	5,374	84,100	16,265
Net income	51,714	55,310	239,773	175,300
Less: Allocations of earnings to unvested restricted stock units	-69	-211	-320	-668
Earnings available to MSCI common shareholders	$51,645	$55,099	$239,453	$174,632
Basic weighted average common shares outstanding	116,251	119,607	116,840	120,497
Effect of dilutive securities:	'	'	'	'
Stock options and restricted stock units	912	971	963	949
Diluted weighted average common shares outstanding	117,163	120,578	117,803	121,446
Earnings per basic common share from continuing operations	$0.44	$0.42	$1.33	$1.32
Earnings per basic common share from discontinued operations	'	$0.04	$0.72	$0.13
Earnings per basic common share	$0.44	$0.46	$2.05	$1.45
Earnings per diluted common share from continuing operations	$0.44	$0.42	$1.32	$1.31
Earnings per diluted common share from discontinued operations	'	$0.04	$0.71	$0.13
Earnings per diluted common share	$0.44	$0.46	$2.03	$1.44

Property_Equipment_and_Leaseho2

Property, Equipment and Leasehold Improvements - Schedule of Property, Equipment and Leasehold Improvements (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Abstract]	'	'
Computer & related equipment	$112,185	$86,384
Furniture & fixtures	9,734	9,108
Leasehold improvements	54,277	52,776
Work-in-process	10,602	12,691
Subtotal	186,798	160,959
Accumulated depreciation and amortization	-93,011	-75,371
Property, equipment and leasehold improvements, net	$93,787	$85,588

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, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Property, Plant and Equipment [Abstract]	'	'	'	'
Depreciation and amortization of property, equipment and leasehold improvements	$6,342	$5,443	$18,091	$14,814

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets - Schedule of Goodwill (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill, Beginning balance	$1,813,164
Changes to goodwill	-244,288
Foreign exchange translation adjustment	-1,433
Goodwill, Ending balance	$1,567,443

Goodwill_and_Intangible_Assets3

Goodwill and Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'	'	'	'
Amortization of intangible assets	$11,574	$11,193	$34,286	$33,581

Goodwill_and_Intangible_Assets4

Goodwill and Intangible Assets - Components of Intangible Assets by Major Class (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	$805,961	$970,084
Accumulated amortization	-360,927	-374,377
Net carrying value	445,034	595,707
Customer relationships [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	360,835	478,735
Accumulated amortization	-112,986	-125,359
Net carrying value	247,849	353,376
Trademarks/trade names [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	223,382	257,282
Accumulated amortization	-78,548	-75,696
Net carrying value	144,834	181,586
Technology/software [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	191,540	199,778
Accumulated amortization	-165,220	-168,481
Net carrying value	26,320	31,297
Proprietary process [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	'	3,800
Accumulated amortization	'	-2,269
Net carrying value	'	1,531
Proprietary data [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	28,627	28,527
Accumulated amortization	-4,043	-2,326
Net carrying value	24,584	26,201
Covenants not to compete [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	900	'
Accumulated amortization	-75	'
Net carrying value	825	'
Subtotal [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	805,284	968,122
Accumulated amortization	-360,872	-374,131
Net carrying value	444,412	593,991
Foreign exchange translation adjustment [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross carrying value	677	1,962
Accumulated amortization	-55	-246
Net carrying value	$622	$1,716

Goodwill_and_Intangible_Assets5

Goodwill and Intangible Assets - Estimated Amortization Expense for Remainder of 2014 and Succeeding Years (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]	'	'
Remainder 2014	$11,647	'
2015	46,929	'
2016	46,413	'
2017	41,186	'
2018	38,436	'
Thereafter	260,423	'
Total	$445,034	$595,707

Commitments_and_Contingencies_1

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

0 Months Ended

3 Months Ended

9 Months Ended

0 Months Ended

9 Months Ended

0 Months Ended

0 Months Ended

9 Months Ended

0 Months Ended

9 Months Ended

0 Months Ended

0 Months Ended

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

Sep. 30, 2014

Sep. 17, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Dec. 31, 2013

Dec. 13, 2012

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Mar. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

4-May-12

Dec. 12, 2013

Dec. 12, 2013

Dec. 12, 2013

4-May-12

Dec. 30, 2013

Jul. 31, 2013

Aug. 01, 2013

Sep. 30, 2014

Sep. 19, 2014

Sep. 19, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Jul. 31, 2013

Dec. 14, 2012

Dec. 13, 2012

5-May-14

Feb. 07, 2014

Feb. 07, 2014

Sep. 17, 2014

Feb. 04, 2014

Foreign Currency Forwards [Member]

Prepaid and Other Assets [Member]

Other Non-Current Assets [Member]

Other Accrued Liabilities [Member]

2012 Term Loan [Member]

2012 Term Loan [Member]

2012 Term Loan [Member]

Senior Secured Revolving Facility [Member]

Senior Secured Revolving Facility [Member]

Quarterly Periods from December 12, 2013 through December 31, 2015 [Member]

Quarterly Periods from January 1, 2016 through September 30, 2018 [Member]

Quarter Ending December 31, 2018 [Member]

Term Loan A [Member]

August 2013 ASR Program [Member]

August 2013 ASR Program [Member]

August 2013 ASR Program [Member]

September 2014 ASR Program [Member]

September 2014 ASR Program [Member]

September 2014 ASR Program [Member]

September 2014 ASR Program [Member]

September 2014 ASR Program [Member]

September 2014 ASR Program [Member]

December 2012 ASR Program [Member]

December 2012 ASR Program [Member]

December 2012 ASR Program [Member]

February 2014 ASR Program [Member]

February 2014 ASR Program [Member]

February 2014 ASR Program [Member]

2014 Repurchase Program [Member]

2014 Repurchase Program [Member]

Derivatives not Designated as Hedging Instruments [Member]

Minimum [Member]

Maximum [Member]

Amended and Restated Credit Facility [Member]

Amended and Restated Credit Facility [Member]

Accelerated Share Repurchase Program [Member]

Accelerated Share Repurchase Program [Member]

Accelerated Share Repurchase Program [Member]

Accelerated Share Repurchase Program [Member]

Accelerated Share Repurchase Program [Member]

Treasury Stock [Member]

Additional Paid in Capital [Member]

Accelerated Share Repurchase Program [Member]

Accelerated Share Repurchase Program [Member]

Accelerated Share Repurchase Program [Member]

Accelerated Share Repurchase Program [Member]

Accelerated Share Repurchase Program [Member]

Accelerated Share Repurchase Program [Member]

Derivative

Accelerated Share Repurchase Program [Member]

Accelerated Share Repurchase Program [Member]

Schedule Of Commitments And Contingencies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Annual rent expense

'

'

$6,300,000

$6,100,000

$19,700,000

$17,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Repurchase program authorizing the purchase of shares

'

'

'

'

'

'

'

300,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

850,000,000

300,000,000

Shares repurchases, value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100,000,000

'

300,000,000

'

'

'

'

'

'

100,000,000

'

'

100,000,000

'

'

Repurchased common shares

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.5

1.9

'

'

'

4.5

'

'

'

0.8

2.2

'

0.6

1.7

'

'

'

Repurchased common shares, average purchase price paid per share

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$41.06

'

'

'

'

'

'

'

'

$33.47

'

'

$43.10

'

'

'

'

Accelerated share repurchase agreement, description

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'On September 18, 2014, the Company entered into a $300.0 million accelerated share repurchase agreement (the "September 2014 ASR Program") with Goldman Sachs & Co. ("GS&Co."), under which, on September 19, 2014, the Company paid GS&Co. $300.0 million in cash and received approximately 4.5 million shares of the Company's common stock and may also receive from GS&Co. additional shares at or prior to maturity of the ASR Agreement.

'

'

'

'

'

'

'

'

'

'

'

'

'

Stockholders equity period increase (decrease)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

300,000,000

210,000,000

-90,000,000

'

'

'

'

'

'

'

'

Quarterly cash dividend, approved date

'

'

'

'

18-Sep-14

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Quarterly cash dividend, payment rate on common stock

'

$0.18

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Quarterly cash dividend, to be paid date

'

'

'

'

31-Oct-14

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Quarterly cash dividend, record date

'

'

'

'

15-Oct-14

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected annual dividend, payment rate on common stock

'

$0.72

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash dividend declared

'

'

'

'

'

'

'

'

'

'

'

20,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Aggregate amount of debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100,000,000

'

'

'

880,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Prepayment of Term Loan

'

'

'

'

'

'

'

'

'

'

'

'

15,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maturity period of the facility

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

31-Dec-18

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt principal repayment

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,100,000

10,100,000

658,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Term loan description

'

'

'

'

'The Company is required to repay $5.1 million in quarterly payments over the first two years and $10.1 million in quarterly payments over the following three years, with the exception of the final payment in December 2018, which will be $658.1 million (assuming no further prepayments).

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Initial bearing interest rate, percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

2.25%

2.40%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Current maturities of long-term debt

'

'

19,781,000

'

19,781,000

'

19,772,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Discount on long-term debt current

'

'

500,000

'

500,000

'

500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt, net of current maturities

'

'

773,173,000

'

773,173,000

'

788,010,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Discount on long-term debt non current

'

'

1,400,000

'

1,400,000

'

1,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Deferred financing fees unamortized

'

'

7,000,000

'

7,000,000

'

'

'

'

1,700,000

5,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amortized deferred financing fees

'

'

400,000

700,000

1,328,000

2,179,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amortization of discount on long-term debt

'

'

100,000

200,000

359,000

699,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair market value of debt obligations

'

'

782,900,000

'

782,900,000

'

812,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Retained earnings restricted as to the payments of dividends

'

'

978,358,000

'

978,358,000

'

758,975,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amount available for restricted payments, after taking into account dividends declared

'

'

'

'

161,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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Foreign currency forwards, notional amount

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$12,000,000

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Number of foreign currency forward

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1

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Commitments_and_Contingencies_2

Commitments and Contingencies - Summary of Fair Values of Derivative Instruments (Detail) (Derivatives not Designated as Hedging Instruments [Member], Other Accrued Liabilities [Member], Foreign Exchange Contracts [Member], USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivatives not Designated as Hedging Instruments [Member] | Other Accrued Liabilities [Member] | Foreign Exchange Contracts [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Liability derivatives	($236)	($156)

Commitments_and_Contingencies_3

Commitments and Contingencies - Interest Rate Swaps and Derivative Instruments (Detail) (Other Expense [Member], Derivatives not Designated as Hedging Instruments [Member], USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
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)	($258)	($1,472)	($825)	($185)

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'	'	'	'
Provision for income taxes	$28,272,000	$27,804,000	$81,937,000	$76,799,000
Effective tax rate	'	'	34.50%	32.60%
Amounts effect on effective tax rate	$3,400,000	$3,500,000	$3,400,000	$3,500,000
Decrease in effective tax rate	'	'	1.40%	1.50%
Significant change in unrecognized tax benefits, reasonably possible (in months)	'	'	'12	'
Significant change in unrecognized tax benefits, not possible (in months)	'	'	'12	'

Segment_Information_Additional

Segment Information - Additional Information (Detail)	0 Months Ended	12 Months Ended	9 Months Ended
	Mar. 17, 2014	Dec. 31, 2013	Sep. 30, 2014
	Segment	Segment	Institutional Shareholder Services Inc. [Member]
Segment Reporting Information [Line Items]	'	'	'
Number of operating segments	1	2	'
Sale completion date	'	'	30-Apr-14

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, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenues	$251,661	$228,608	$745,575	$676,500
United States [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenues	118,721	104,917	347,779	308,341
Other [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenues	9,171	8,993	27,961	24,529
Total Americas [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenues	127,892	113,910	375,740	332,870
United Kingdom [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenues	40,104	35,758	115,961	103,485
Other [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenues	52,067	49,418	160,695	152,826
Total EMEA [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenues	92,171	85,176	276,656	256,311
Japan [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenues	11,573	11,919	35,385	35,156
Other [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenues	20,025	17,603	57,794	52,163
Total Asia & Australia [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenues	$31,598	$29,522	$93,179	$87,319

Segment_Information_LongLived_

Segment Information - Long-Lived Assets by Geographic Area (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Long-lived assets	$2,106,264	$2,494,459
United States [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Long-lived assets	1,953,113	2,338,124
Other [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Long-lived assets	3,719	4,082
Total Americas [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Long-lived assets	1,956,832	2,342,206
United Kingdom [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Long-lived assets	126,749	133,411
Other [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Long-lived assets	11,933	11,871
Total EMEA [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Long-lived assets	138,682	145,282
Japan [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Long-lived assets	987	1,543
Other [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Long-lived assets	9,763	5,428
Total Asia & Australia [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Long-lived assets	$10,750	$6,971

Acquisitions_Additional_Inform

Acquisitions - Additional Information (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Aug. 11, 2014	Sep. 30, 2014
			GMI Ratings [Member]	GMI Ratings [Member]
				Companies
Business Acquisition [Line Items]	'	'	'	'
Company paid cash to acquire property	'	'	$15,500,000	'
Date of acquisition	'	'	'	11-Aug-14
Number of companies for which corporate governance research and ratings provided	'	'	'	6,000
Purchase price allocated to goodwill	1,567,443,000	1,813,164,000	'	9,900,000
Purchase price allocated to identifiable intangible assets	'	'	'	3,600,000
Purchase price allocated for assets other than identifiable intangible assets	'	'	'	8,100,000
Purchase price allocated to other liabilities	'	'	'	$6,100,000