MSCI (MSCI) 10-K 26 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 16, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	MSCI
Entity Registrant Name	MSCI Inc.
Entity Central Index Key	1,408,198
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		89,944,256
Entity Public Float			$ 9,086,723,896

Consolidated Statements of Fina

Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 889,502	$ 791,834
Accounts receivable (net of allowances of $1,700 and $1,035 at December 31, 2017 and December 31, 2016, respectively)	327,597	221,504
Prepaid income taxes	15,103	12,389
Prepaid and other assets	34,927	29,943
Total current assets	1,267,129	1,055,670
Property, equipment and leasehold improvements (net of accumulated depreciation and amortization of $171,280 and $136,841 at December 31, 2017 and December 31, 2016, respectively)	94,437	95,585
Goodwill	1,560,621	1,555,850
Intangible assets (net of accumulated amortization of $507,612 and $462,860 at December 31, 2017 and December 31, 2016, respectively)	321,836	347,640
Deferred tax assets	12,013	9,531
Other non-current assets	19,632	18,302
Total assets	3,275,668	3,082,578
Current liabilities:
Accounts payable	1,612	568
Accrued compensation and related benefits	131,156	119,113
Other accrued liabilities	100,538	82,531
Deferred revenue	374,365	334,358
Total current liabilities	607,671	536,570
Long-term debt	2,078,093	2,075,201
Deferred taxes	78,027	94,067
Other non-current liabilities	110,865	59,135
Total liabilities	2,874,656	2,764,973
Commitments and Contingencies (see Note 4 and Note 8)
Shareholders' equity:
Preferred Stock (par value $0.01, 100,000,000 share authorized, no shares issued)
Common stock (par value $0.01; 750,000,000 common shares authorized; 129,543,856 and 128,996,344 common shares issued and 90,104,885 and 91,279,590 common shares outstanding at December 31, 2017 and December 31, 2016, respectively)	1,295	1,290
Treasury shares, at cost (39,438,971 and 37,716,754 common shares held at December 31, 2017 and December 31, 2016, respectively)	(2,321,989)	(2,170,739)
Additional paid in capital	1,264,849	1,225,565
Retained earnings	1,505,204	1,322,224
Accumulated other comprehensive loss	(48,347)	(60,735)
Total shareholders' equity	401,012	317,605
Total liabilities and shareholders' equity	$ 3,275,668	$ 3,082,578

Consolidated Statements of Fin3

Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Accounts receivable, allowances	$ 1,700	$ 1,035
Property, equipment and leasehold improvements, accumulated depreciation and amortization	171,280	136,841
Intangible assets, accumulated amortization	$ 507,612	$ 462,860
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	129,543,856	128,996,344
Common stock, shares outstanding	90,104,885	91,279,590
Treasury shares	39,438,971	37,716,754

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Operating revenues	$ 334,779	$ 322,097	$ 316,089	$ 301,207	$ 292,812	$ 288,433	$ 290,596	$ 278,828					$ 1,274,172	$ 1,150,669	$ 1,075,013
Operating expenses:
Cost of revenues	69,306	68,491	68,595	67,521	63,819	62,986	62,130	63,172					273,913	252,107	267,695
Selling and marketing	47,771	44,918	41,594	43,014	41,609	41,514	41,854	41,689					177,297	166,666	162,294
Research and development	20,721	17,983	18,203	18,977	18,960	18,750	18,566	18,928					75,884	75,204	77,320
General and administrative	23,348	22,103	21,448	21,004	21,467	21,859	22,019	21,890					87,903	87,235	86,007
Amortization of intangible assets	11,560	10,614	11,122	11,251	11,498	11,752	11,943	11,840					44,547	47,033	46,910
Depreciation and amortization of property, equipment and leasehold improvements	8,118	9,325	9,159	8,838	9,447	8,312	8,393	8,168					35,440	34,320	30,889
Total operating expenses	180,824	173,434	170,121	170,605	166,800	165,173	164,905	165,687					694,984	662,565	671,115
Operating income	153,955	148,663	145,968	130,602	126,012	123,260	125,691	113,141					579,188	488,104	403,898
Interest income	(2,237)	(1,835)	(1,310)	(932)	(901)	(799)	(585)	(621)					(6,314)	(2,906)	(1,166)
Interest expense	29,027	29,020	29,027	29,024	29,039	26,790	22,918	22,904					116,098	101,651	62,387
Other expense (income)	205	675	740	885	779	(253)	2,814	81					2,505	3,421	(6,877)
Other expense (income), net	26,995	27,860	28,457	28,977	28,917	25,738	25,147	22,364					112,289	102,166	54,344
Income from continuing operations before provision for income taxes	126,960	120,803	117,511	101,625	97,095	97,522	100,544	90,777					466,899	385,938	349,554
Provision for income taxes	62,358	35,650	36,245	28,674	28,845	32,241	33,587	30,410					162,927	125,083	119,516
Income from continuing operations													303,972	260,855	230,038
Loss from discontinued operations, net of income taxes															(6,390)
Net income	$ 64,602	$ 85,153	$ 81,266	$ 72,951	$ 68,250	$ 65,281	$ 66,957	$ 60,367					$ 303,972	$ 260,855	$ 223,648
Earnings per basic common share:
Earnings per basic common share from continuing operations													$ 3.36	$ 2.72	$ 2.11
Loss per basic common share from discontinued operations															(0.06)
Earnings per basic common share	$ 0.72	$ 0.94	$ 0.90	$ 0.80	$ 0.73	$ 0.69	$ 0.69	$ 0.61					3.36	2.72	2.05
Earnings per diluted common share:
Earnings per diluted common share from continuing operations													3.31	2.70	2.09
Loss per diluted common share from discontinued operations															(0.06)
Earnings per diluted common share	$ 0.70	$ 0.93	$ 0.89	$ 0.80	$ 0.73	$ 0.68	$ 0.69	$ 0.60					$ 3.31	$ 2.70	$ 2.03
Weighted average shares outstanding used in computing earnings per share:
Basic	90,130	90,112	90,404	90,708	93,327	94,823	96,412	99,425					90,336	95,986	109,124
Diluted	92,467	91,868	91,708	91,624	93,845	95,473	96,888	99,998					91,914	96,540	109,926
Dividend declared per common share	$ 0.38	$ 0.38	$ 0.28	$ 0.28	$ 0.28	$ 0.28	$ 0.22	$ 0.22	$ 0.22	$ 0.22	$ 0.18	$ 0.18	$ 1.32	$ 1	$ 0.80

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 303,972	$ 260,855	$ 223,648
Other comprehensive income (loss):
Foreign currency translation adjustments	13,358	(24,871)	(12,253)
Income tax effect		(714)	135
Foreign currency translation adjustments, net	13,358	(25,585)	(12,118)
Pension and other post-retirement adjustments	(525)	660	1,872
Income tax effect	(445)	(65)	(528)
Pension and other post-retirement adjustments, net	(970)	595	1,344
Other comprehensive income (loss), net of tax	12,388	(24,990)	(10,774)
Comprehensive income	$ 316,360	$ 235,865	$ 212,874

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2014	$ 1,432,833	$ 1,266	$ (588,378)	$ 1,022,221	$ 1,022,695	$ (24,971)
Net income	223,648				223,648
Dividends	(87,852)			29	(87,881)
Other comprehensive income (loss), net of tax	(10,774)					(10,774)
Common stock issued	6	6
Compensation payable in common stock and options	25,963			25,963
Common stock repurchased and held in treasury	(716,782)		(806,782)	90,000
Common stock issued to directors and held in treasury	(506)		(535)	29
Exercise of stock options	19,698	10		19,688
Excess tax benefits from employee stock incentive plans	15,253			15,253
Balance at Dec. 31, 2015	901,487	1,282	(1,395,695)	1,173,183	1,158,462	(35,745)
Net income	260,855				260,855
Dividends	(97,059)			34	(97,093)
Other comprehensive income (loss), net of tax	(24,990)					(24,990)
Common stock issued	5	5
Compensation payable in common stock and options	39,648			39,648
Common stock repurchased and held in treasury	(774,565)		(774,565)
Common stock issued to directors and held in treasury	(441)		(479)	38
Exercise of stock options	5,040	3		5,037
Excess tax benefits from employee stock incentive plans	7,625			7,625
Balance at Dec. 31, 2016	317,605	1,290	(2,170,739)	1,225,565	1,322,224	(60,735)
Net income	303,972				303,972
Dividends	(120,972)			20	(120,992)
Other comprehensive income (loss), net of tax	12,388					12,388
Common stock issued	4	4
Compensation payable in common stock and options	36,572			36,572
Common stock repurchased and held in treasury	(150,461)		(150,461)
Common stock issued to directors and held in treasury	(731)		(789)	58
Exercise of stock options	2,635	1		2,634
Balance at Dec. 31, 2017	$ 401,012	$ 1,295	$ (2,321,989)	$ 1,264,849	$ 1,505,204	$ (48,347)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Cash flows from operating activities
Net income	$ 303,972	$ 260,855	$ 223,648
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of intangible assets	44,547	47,033	46,910
Stock-based compensation expense	36,576	32,001	28,558
Depreciation and amortization of property, equipment and leasehold improvements	35,440	34,320	30,889
Amortization of debt origination fees	3,396	3,068	2,135
Deferred taxes	(18,902)	(16,967)	(10,288)
Gain on disposition		(449)
Other non-cash adjustments	704	1,192	(2,067)
Changes in assets and liabilities, net of the effect of acquisitions and dispositions:
Accounts receivable	(105,593)	(18,494)	(30,900)
Prepaid income taxes	(3,069)	41,332	(1,972)
Prepaid and other assets	(4,470)	624	(1,217)
Accounts payable	1,027	(1,912)	(298)
Accrued compensation and related benefits	8,659	13,089	5,087
Other accrued liabilities	15,933	19,741	17,165
Deferred revenue	38,555	21,809	8,047
Other	47,383	5,121	5,550
Net cash provided by operating activities	404,158	442,363	321,247
Cash flows from investing activities
Proceeds from sales of investments	771		6,736
Disposition, net of cash provided		657
Proceeds from the sale of capital equipment			55
Capital expenditures	(33,177)	(32,284)	(40,652)
Capitalized software development costs	(15,640)	(10,344)	(8,500)
Acquisitions, net of cash acquired		(60)	(6,500)
Net cash used in investing activities	(48,046)	(42,031)	(48,861)
Cash flows from financing activities
Proceeds from borrowing		500,000	800,000
Proceeds from exercise of stock options	2,635	5,040	3,631
Repurchase of treasury shares	(150,461)	(774,565)	(700,715)
Payment of dividends	(119,717)	(96,191)	(87,743)
Payment of debt issuance costs in connection with debt		(7,183)	(10,477)
Net cash (used in) provided by financing activities	(267,543)	(372,899)	4,696
Effect of exchange rate changes	9,099	(13,305)	(8,175)
Net increase in cash	97,668	14,128	268,907
Cash and cash equivalents, beginning of period	791,834	777,706	508,799
Cash and cash equivalents, end of period	889,502	791,834	777,706
Supplemental disclosure of cash flow information:
Cash paid for interest	112,502	89,139	42,110
Cash paid for income taxes	128,727	97,845	129,534
Supplemental disclosure of non-cash investing activities
Property, equipment and leasehold improvements in other accrued liabilities	4,588	4,422	3,644
Supplemental disclosure of non-cash financing activities
Cash dividends declared, but not yet paid	$ 1,197	$ 830	$ 84

Consolidated Statements of Cas8

Consolidated Statements of Cash Flows (Parenthetical) $ in Millions	Dec. 31, 2017USD ($)
Statement Of Cash Flows [Abstract]
Accrued amount payable	$ 43.6

Introduction and Basis of Prese

Introduction and Basis of Presentation	12 Months Ended
	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Introduction and Basis of Presentation	1. INTRODUCTION AND BASIS OF PRESENTATION Organization MSCI Inc., together with its wholly-owned subsidiaries (the “Company” or “MSCI”), provides mission-critical investment decision support tools, including indexes; portfolio construction and risk management products and services; Environmental, Social and Governance (“ESG”) research and ratings; and real estate research, reporting and benchmarking offerings. MSCI’s research-derived intellectual property includes methodologies, models, derived data and algorithms, as well as applications and services, which help its clients manage their investment processes and address their investment, risk and regulatory challenges. On March 17, 2014, MSCI Inc. 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 (loss) from discontinued operations, net of income taxes” in the Consolidated Statements of Income for the year ended December 31, 2015. Unless otherwise indicated, the disclosures accompanying these consolidated financial statements reflect the Company’s continuing operations. See Note 11, “Acquisitions and Dispositions,” for further details. Basis of Presentation The consolidated financial statements include the accounts of MSCI Inc. and its wholly-owned subsidiaries. The Company’s policy is to consolidate all entities in which it owns more than 50% of the outstanding voting stock unless it does not control the entity. It is also the Company’s policy to consolidate any variable interest entity for which the Company is the primary beneficiary, as required by the Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification (“ASC”) Subtopic 810-10, “ Consolidations.” The Company’s operating expenses are grouped and presented in the following activity categories: cost of revenues, selling and marketing, research and development and general and administrative. Costs are assigned to these activity categories based on the nature of the expense to which they directly relate, or, when not directly attributable, based on an allocation method that considers the type of effort related to such activities. Cost of revenues consists of costs related to the production and servicing of the Company’s products and services and primarily includes related information technology costs, including data center, platform and infrastructure costs; costs to acquire, produce and maintain market data information; costs of research to support, maintain existing products; costs of product management teams; costs of client service and consultant teams to support customer needs; as well as other support costs directly attributable to the cost of revenues including certain human resources, finance and legal costs. Selling and marketing expenses consist of costs associated with acquiring new clients or selling new products or product renewals to existing clients and primarily includes the costs of MSCI’s sales force and marketing teams as well as costs incurred in other groups associated with acquiring new business, including product management, research, technology and sales operations. Research and development expenses consist of costs to develop new or enhance existing products and the costs to develop new or improved technology and service platforms for the delivery of MSCI’s products and services and primarily includes the costs of development, research, product management, project management and the technology support associated with these efforts. General and administrative expenses consist of costs primarily related to finance operations, human resources, office of the CEO, legal, corporate technology, corporate development and certain other administrative costs that are not directly attributed, but are instead allocated, to a product or service. Significant Accounting Policies Basis of Financial Statements and Use of Estimates The Company’s 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 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, impairment of long-lived assets, accrued compensation, income taxes and other matters that affect the consolidated financial statements and related disclosures. The Company believes that estimates used in the preparation of these consolidated financial statements are reasonable; however, actual results could differ materially from these estimates. Inter-company balances and transactions are eliminated in consolidation. Revenue Recognition The Company applies SEC Staff Accounting Bulletin No. 104 (“SAB 104”), “ Revenue Recognition, • the Company has persuasive evidence of a legally binding arrangement, • delivery has occurred, • client fee is deemed fixed or determinable, and • collection is reasonably assured. When a sales arrangement requires the delivery of more than one product and service, revenue is recognized pursuant to the requirements of ASC Subtopic 605-25, “ Revenue Arrangements with Multiple Deliverables. • the delivered items have value to the client on a standalone basis, which means they can be sold separately by any vendor or the client could resell the delivered items on a standalone basis; and • if the arrangement includes a general right of return relative to the delivered items, delivery or performance of the undelivered items is considered probable and substantially in the control of the vendor. The Company has signed contracts or agreements with substantially all clients that set forth the fees to be paid for its products and services. Further, the Company regularly assesses the receivable balances for each client for collectability. The Company’s application service license arrangements generally do not include acceptance provisions, which generally allow a client to test the solution for a defined period of time before committing to the license. If a license agreement includes an acceptance provision, the Company does not recognize subscription revenues until the earlier of the receipt of a written client acceptance or, if not notified by the client that it is cancelling the license agreement, the expiration of the acceptance period. The Company’s subscription agreements for hosted services include provisions that, among other things, allow clients, for no additional fee, to receive updates and modifications that may be made from time to time when and if available, for the term of the agreement, which is typically one year. These arrangements do not provide the client with the right to take possession of the application at any time. For sales arrangements with multiple deliverables, which may include application service subscription and professional services associated with implementation and other services, the Company evaluates each deliverable in these multiple-element arrangements to determine whether it represents a separate unit of accounting and allocates revenue accordingly, based on the Company’s best estimated sales price. In most cases, the Company recognizes revenues from subscription arrangements ratably over the term of the license agreement pursuant to the contract’s terms. The contracts state the terms under which these fees are to be calculated. The fees are recognized as the Company supplies the product and service to the client over the license period and are generally billed in advance, prior to the license start date. When implementation services are included, the Company recognizes revenues allocated to the subscription ratably from the date the application is put into production to the end of the license period. Revenues associated with implementation services are recognized ratably over the useful life of those services from the date the application is put into production. For products and services whose fees are based on estimated assets under management linked to the Company’s indexes, or contract values related to futures and options, the Company recognizes revenues based on estimates from independent third-party sources or the most recently reported information from the client. Revenues from subscription agreements for the receipt of periodic benchmark reports, digests, and other publications, which are most often associated with the Company’s real estate operating segment, are primarily recognized upon delivery of such reports or data updates. The Company’s software-related arrangements do not require significant modification or customization of any underlying software applications being licensed. Accordingly, the Company recognizes software revenues pursuant to the requirements of ASC Subtopic 985-605, “ Software—Revenue Recognition.” Software—Revenue Recognition, Share-Based Compensation Certain of the Company’s employees have received share-based compensation under various compensation programs. The Company’s compensation expense reflects the fair value method of accounting for share-based payments under ASC Subtopic 718-10, “ Compensation—Stock Compensation. The fair value of MSCI restricted stock units (“RSUs”) is measured using the closing price of MSCI’s common stock on the date prior to grant. Restricted stock units subject to performance conditions (“PSUs”) are based on performance measures that impact the amount of shares that each recipient will receive upon vesting. The fair value of PSUs is measured using the closing price of MSCI’s common stock on the date prior to grant. Restricted stock units that are subject to the achievement of multi-year total shareholder return targets (“MSUs”) are performance awards with a market condition. The fair value of MSUs is determined using a Monte Carlo simulation model that creates a normal distribution of future stock prices, which is then used to value the awards based on their individual terms. The fair value of MSCI standard stock options is determined using the Black-Scholes valuation model and the single grant life method. Under the single grant life method, option awards with graded vesting are valued using a single weighted-average expected option life. The fair value of MSCI stock options that contain stock price contingencies is determined using a Monte Carlo simulation model. The Company recognizes the expense for an award granted to an employee who is not retirement-eligible utilizing the graded vesting method over the requisite service period. For all awards, the Company bases initial accruals of compensation cost on the estimated number of units for which the requisite service is expected to be rendered and, for PSUs, the performance targets expected to be achieved is also considered. If the estimated number of units or the number of units ultimately delivered changes from previous estimates, the cumulative effect on current and prior periods of a change is recognized in compensation cost in the period of the change. Because the probability of actual shares expected to be earned is reflected in the fair value of MSUs on the grant date, the expense to be recognized for these awards is not adjusted to reflect the actual shares earned. Based on interpretive guidance related to share-based compensation, the Company’s policy is to accrue the estimated cost of share-based awards that are granted to retirement-eligible employees over the course of the prior year in which they were earned rather than expensing the awards on the date of grant. A portion of the awards granted to retirement-eligible employees consisted of PSUs. For those PSUs, the Company bases initial accruals of compensation cost on the estimated number of units for which the requisite service is expected to be rendered. If the estimated number of units expected to convert changes from previous estimates based on the performance targets expected to be achieved, the cumulative effect of a change is recognized in compensation cost in the period of the change. Research and Development The Company accounts for research and development costs in accordance with several accounting pronouncements, including ASC Subtopic 730-10, “ Research and Development The Company applies the provisions of ASC Subtopic 350-40, “ Internal Use Software For the year ended December 31, 2017, the Company capitalized $15.6 million of costs related to software developed for internal use in the Consolidated Statement of Financial Condition for the year ended December 31, 2017. For the year ended December 31, 2016, the Company capitalized $10.3 million of costs related to software developed for internal use in the Consolidated Statement of Financial Condition for the year ended December 31, 2016. Capitalized software development costs are amortized on a straight-line basis over the estimated useful life of the related product, which is typically three to five years, beginning with the date the software is placed into service. Costs incurred in the preliminary and post-implementation stages of MSCI’s products are expensed as incurred. Income Taxes Income tax expense is provided for using the asset and liability method, under which deferred tax assets and deferred tax liabilities are determined based on the temporary differences between the financial statement and income tax bases of assets and liabilities using currently enacted tax rates. The Company recognizes interest and penalties related to income tax matters within “Provision for income taxes” in the Consolidated Statement of Income. The Company regularly evaluates the likelihood of additional assessments in each of the taxing jurisdictions in which it is required to file income tax returns. The Company has recorded additional tax expense related to open tax years, which the Company’s management believes is adequate in relation to the potential for assessments. These amounts have been recorded in “Other non-current liabilities” on the Consolidated Statement of Financial Condition. The Company’s management believes the resolution of tax matters will not have a material effect on the Company’s consolidated financial condition. However, to the extent the Company is required to pay amounts in excess of its reserves, a resolution could have a material impact on its Consolidated Statement of Income for a particular future period. In addition, an unfavorable tax settlement could require use of cash and result in an increase in the effective tax rate in the period in which such resolution occurs. Deferred Revenue Deferred revenues represent amounts billed to customers for products and services in advance of delivery. The Company’s clients generally pay subscription fees annually or quarterly in advance. Deferred revenue is generally amortized ratably over the service period as revenue recognition criteria are met. Where the service period has not begun and the client has not paid or the contract has not been renewed, deferred revenues and accounts receivable are not recognized. Goodwill Goodwill is recorded as part of the Company’s acquisitions of businesses when the purchase price exceeds the fair value of the net tangible and separately identifiable intangible assets acquired. The Company’s goodwill is not amortized, but rather is subject to an impairment test each year, or more often if conditions indicate impairment may have occurred, pursuant to ASC Subtopic 350-10, “ Intangibles—Goodwill and Other The Company tests goodwill for impairment on an annual basis on July 1 and on an interim basis when certain events and circumstances exist. The testing for impairment is performed at the reporting unit level. Goodwill impairment is determined by comparing the fair value of a reporting unit with its carrying value. If the estimated fair value exceeds the carrying value, goodwill at the reporting unit level is not deemed to be impaired. If the estimated fair value is below carrying value, however, further analysis is required to determine the amount of impairment, if any. If necessary an impairment charge will be recorded up to, but not more than, the total amount of goodwill allocated to the reporting unit. The Company completed its annual goodwill impairment test as of July 1, 2017 on its four reporting units, which are the same as its four operating segments. The Company performed a step zero, qualitative impairment test on each of its Index, Analytics and ESG operating segments and determined that it was more likely than not that the fair value for each of the Index, Analytics and ESG operating segments was not less than the carrying value for each. As revenues have been below management’s expectations for the Real Estate segment, the Company performed a step 1, quantitative impairment test for this segment and determined that the fair value substantially exceeded its carrying value. As the estimated fair value of the Company’s reporting units exceeded their carrying value on the testing dates, no impairment of goodwill was recorded during the years ended December 31, 2017, 2016 and 2015. Intangible Assets The Company amortizes definite-lived intangible assets over their estimated useful lives. Definite-lived intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value of the asset may not be recoverable. The Company also reviews the useful lives on a quarterly basis to determine if the period of economic benefit has changed. If the carrying value of an intangible asset exceeds its fair value an impairment charge would be recognized in an amount equal to the amount by which the carrying value of the intangible asset exceeds its fair value. The Company has not identified a triggering event during any of the periods presented and as such has not recorded any impairment charges . The Company had no indefinite-lived intangibles. Foreign Currency Translation Assets and liabilities of operations having non-U.S. dollar functional currencies are translated at year-end exchange rates, and income statement accounts are translated at weighted average exchange rates for the year. Gains or losses resulting from translating foreign currency financial statements, net of related tax effects, are reflected in accumulated other comprehensive loss, a separate component of shareholders’ equity. Gains or losses resulting from foreign currency transactions incurred in currencies other than the local functional currency are included in non-operating “Other expense (income)” on the Consolidated Statement of Income. Derivative Instruments The Company applies ASC Subtopic 815-10, “ Derivatives and Hedging, For derivative instruments that are designated and qualify as hedging instruments for accounting purposes, the Company documents and links the relationships between the hedging instruments and hedged items. The Company also assesses and documents at the hedge’s inception whether the derivatives used in hedging transactions were effective in offsetting changes in fair values associated with the hedged items. ASC Subtopic 815-10 provides that, for derivative instruments that qualify for hedge accounting being used to hedge cash flows, changes in the fair value are recognized in accumulated other comprehensive income (loss), a separate component of shareholders’ equity, until the hedged item is recognized in earnings. In addition, the ineffective portion of a derivative’s change in fair value is immediately recognized in earnings. The Company manages foreign currency exchange rate risk through the use of derivative financial instruments comprised principally of forward contracts on foreign currency which are not designated as hedging instruments for accounting purposes. The objective of the derivative instruments is to minimize the income statement impact associated with assets and liabilities that are denominated in certain foreign currencies. Derivative instruments that do not qualify for hedge accounting are carried at fair value on the Consolidated Statement of Financial Condition with gains and losses recorded in the Consolidated Statement of Income in the period in which they are realized. Property, Equipment and Leasehold Improvements Property, equipment and leasehold improvements are stated at cost less accumulated depreciation and amortization. Depreciation of furniture and fixtures and computer and communications equipment are amortized using the straight-line method over the estimated useful life of the asset. Treasury Stock The Company holds repurchased shares of common stock as treasury stock. The Company accounts for treasury stock under the cost method and includes treasury stock as a component of shareholders’ equity. In accordance with ASC Subtopic 505-10, “ Equity Allowance for Doubtful Accounts The Company primarily licenses its products and services to institutional investors mainly in the United States, Europe and Asia (primarily Hong Kong and Japan). The Company periodically reviews receivable balances and maintains an allowance on customer accounts where estimated losses may result from the inability of its customers to make required payments. The Company does not require collateral. An allowance for doubtful accounts is recorded when it is probable and estimable that a receivable will not be collected. Changes in the allowance for doubtful accounts from December 31, 2014 to December 31, 2017 were as follows: Amount (in Balance as of December 31, 2014 $ 857 Addition to provision 940 Amounts written off, net of recoveries (680 ) Balance as of December 31, 2015 $ 1,117 Addition to provision 1,011 Amounts written off, net of recoveries (1,093 ) Balance as of December 31, 2016 $ 1,035 Addition to provision 1,422 Amounts written off, net of recoveries (757 ) Balance as of December 31, 2017 $ 1,700 Accrued Compensation The Company makes significant estimates in determining its accrued non-stock based compensation and benefits expenses. A significant portion of the Company’s employee incentive compensation programs are discretionary. At the end of each fiscal year, the Company determines the amount of discretionary cash bonus expense. These estimates reflect an assessment of performance versus targets and other key performance indicators at the Company, operating segment and employee level. The Company also reviews compensation and benefits expenses throughout the year to determine how overall performance compares to management’s expectations. These and other factors, including historical performance, are taken into account in accruing discretionary cash compensation estimates quarterly. Concentrations For the years ended December 31, 2017 and 2015, BlackRock, Inc. accounted for 11.5% and 10.3%, respectively, of the Company’s consolidated operating revenues while no single customer represented 10.0% or more of the Company’s consolidated operating revenues for the year ended December 31, 2016. For the years ended December 31, 2017, 2016 and 2015, BlackRock, Inc. accounted for 20.0%, 17.3% and 19.2%, respectively, of the Index segment’s operating revenues. No single customer accounted for 10.0% or more of operating revenues within the Analytics and All Other segments for the years ended December 31, 2017, 2016 and 2015.

Recent Accounting Standards Upd

Recent Accounting Standards Updates	12 Months Ended
	Dec. 31, 2017
Accounting Changes And Error Corrections [Abstract]
Recent Accounting Standards Updates	2. RECENT ACCOUNTING STANDARDS UPDATES In May 2014, the FASB issued Accounting Standards Update 2014-09, “Revenue from Contracts with Customers (Topic 606),” “Deferral of the Effective Date,” In March 2016, the FASB issued Accounting Standards Update 2016-08, “ Principal Versus Agent Considerations (Reporting Revenue Gross Versus Net). Identifying Performance Obligations and Licensing. Narrow-Scope Improvements and Practical Expedients. Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers. In February 2016, the FASB issued Accounting Standards Update No. 2016-02, “ Leases (Topic 842), In March 2016, the FASB issued Accounting Standards Update No. 2016-09, “ Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting In June 2016, the FASB issued Accounting Standards Update No. 2016-13, “ Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, In January 2017, the FASB issued Accounting Standards Update No. 2017-01, “ Business Combinations (Topic 805): Clarifying the Definition of a Business, In January 2017, the FASB issued Accounting Standards Update No. 2017-04, “ Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, In February 2017, the FASB issued Accounting Standards Update No. 2017-07, “ Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost, In May 2017, the FASB issued Accounting Standards Update No. 2017-09, “ Compensation—Stock Compensation (Topic 718), Scope of Modification Accounting, In August 2017, the FASB issued Accounting Standards Update No. 2017-12, “ Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities, On December 22, 2017 the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (“Tax Reform”). Given the significance of the legislation, the SEC staff issued Staff Accounting Bulletin No. 118, “ Income Tax Accounting Implications of the Tax Cuts and Jobs Act,

Earnings Per Common Share

Earnings Per Common Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Common Share	3. 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 987, 398 and 3,778 anti-dilutive securities excluded from the calculation of diluted EPS for the years ended December 31, 2017, 2016 and 2015, respectively, because of their anti-dilutive effect. The following table presents the computation of basic and diluted EPS: Years Ended December 31, December 31, December 31, 2017 2016 2015 (in thousands, except per share data) Income from continuing operations, net of income taxes $ 303,972 $ 260,855 $ 230,038 Loss from discontinued operations, net of income taxes — — (6,390 ) Net income $ 303,972 $ 260,855 $ 223,648 Basic weighted average common shares outstanding 90,336 95,986 109,124 Effect of dilutive securities: Stock options and restricted stock units 1,578 554 802 Diluted weighted average common shares outstanding 91,914 96,540 109,926 Earnings per basic common share from continuing operations $ 3.36 $ 2.72 $ 2.11 Loss per basic common share from discontinued operations — — (0.06 ) Earnings per basic common share $ 3.36 $ 2.72 $ 2.05 Earnings per diluted common share from continuing operations $ 3.31 $ 2.70 $ 2.09 Loss per diluted common share from discontinued operations — — (0.06 ) Earnings per diluted common share $ 3.31 $ 2.70 $ 2.03

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	4. 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 years ended December 31, 2017, 2016 and 2015 was $24.2 million, $24.2 million and $26.5 million, respectively. Future minimum commitments for the Company’s operating leases in place as of December 31, 2017 are as follows: Years Ending December 31, Amount (in 2018 $ 30,210 2019 25,346 2020 21,943 2021 19,094 2022 16,208 Thereafter 117,853 Total $ 230,654 Senior Notes. The Company has issued an aggregate of $2.1 billion in senior unsecured notes (collectively, the “Senior Notes”) in the three discrete private offerings described below. On November 20, 2014, the Company completed its private offering of $800.0 million aggregate principal amount of 5.25% senior unsecured notes due 2024 (the “2024 Senior Notes”). The Company used the net proceeds from the offering of the 2024 Senior Notes, together with cash on hand, to repay in full its then outstanding term loan indebtedness of $794.8 million. On August 13, 2015, the Company completed its private offering of $800.0 million aggregate principal amount of 5.75% senior unsecured notes due 2025 (the “2025 Senior Notes”). The $789.5 million of net proceeds from the offering of the 2025 Senior Notes were allocated for general corporate purposes. On August 4, 2016, the Company completed its private offering of $500.0 million aggregate principal amount of 4.75% senior unsecured notes due 2026 (the “2026 Senior Notes”). The $493.3 million of net proceeds from the offering of the 2026 Senior Notes were allocated for general corporate purposes, including, without limitation, buybacks of its common stock and potential acquisitions. The 2024 Senior Notes are scheduled to mature and be paid in full on November 15, 2024. At any time prior to November 15, 2019, the Company may redeem all or part of the 2024 Senior Notes upon not less than 30 nor more than 60 days’ prior notice at a redemption price equal to the sum of (i) 100% of the principal amount thereof, plus (ii) a make-whole premium as of the date of redemption, plus (iii) accrued and unpaid interest and additional interest, if any, thereon, to the date of redemption. In addition, the Company may redeem all or part of the 2024 Senior Notes, together with accrued and unpaid interest, on or after November 15, 2019, at redemption prices set forth in the indenture governing the 2024 Senior Notes. The 2025 Senior Notes are scheduled to mature and be paid in full on August 15, 2025. At any time prior to August 15, 2020, the Company may redeem all or part of the 2025 Senior Notes upon not less than 30 nor more than 60 days’ prior notice at a redemption price equal to the sum of (i) 100% of the principal amount thereof, plus (ii) a make-whole premium as of the date of redemption, plus (iii) accrued and unpaid interest and additional interest, if any, thereon, to the date of redemption. In addition, the Company may redeem all or part of the 2025 Senior Notes, together with accrued and unpaid interest, on or after August 15, 2020, at redemption prices set forth in the indenture governing the 2025 Senior Notes. At any time prior to August 15, 2018, the Company may use the proceeds of certain equity offerings to redeem up to 35% of the aggregate principal amount of the 2025 Senior Notes, including any permitted additional notes, at a redemption price equal to 105.75% of the principal amount. The 2026 Senior Notes are scheduled to mature and be paid in full on August 1, 2026. At any time prior to August 1, 2021, the Company may redeem all or part of the 2026 Senior Notes upon not less than 30 nor more than 60 days’ prior notice at a redemption price equal to the sum of (i) 100% of the principal amount thereof, plus (ii) a make-whole premium as of the date of redemption, plus (iii) accrued and unpaid interest and additional interest, if any, thereon, to the date of redemption. In addition, the Company may redeem all or part of the 2026 Senior Notes, together with accrued and unpaid interest, on or after August 1, 2021, at redemption prices set forth in the indenture governing the 2026 Senior Notes. At any time prior to August 1, 2019, the Company may use the proceeds of certain equity offerings to redeem up to 35% of the aggregate principal amount of the 2026 Senior Notes, including any permitted additional notes, at a redemption price equal to 104.75% of the principal amount. Interest payments attributable to the 2024 Senior Notes are due on May 15 and November 15 of each year. Interest payments attributable to the 2025 Senior Notes are due on February 15 and August 15 of each year. Interest payments attributable to the 2026 Senior Notes are due on February 1 and August 1 of each year. Revolver. On November 20, 2014, the Company entered into a $200.0 million senior unsecured revolving credit agreement (the “2014 Revolving Credit Agreement”) with a syndicate of banks. The 2014 Revolving Credit Agreement had an initial term of five years with an option to extend for two additional one-year terms. On August 4, 2016, the Company entered into Amendment No. 1 (the “Amendment”) to the 2014 Revolving Credit Agreement (the 2014 Revolving Credit Agreement as so amended, the “Revolving Credit Agreement”). The Amendment, among other things, (i) increased aggregate commitments available to be borrowed to $220.0 million, (ii) increased the maximum consolidated leverage ratio and (iii) extended the initial term to August 2021 with an option to extended for an additional one-year term. At December 31, 2017, the Revolving Credit Agreement was undrawn. Long-term debt at December 31, 2017 was $2,078.1 million, net of $21.9 million in deferred financing fees. Long-term debt at December 31, 2016 was $2,075.2 million, net of $24.8 million in deferred financing fees. In connection with the closings of the Senior Notes offerings and entering into the 2014 Revolving Credit Agreement and the Amendment, the Company paid certain fees which, together with the existing fees related to prior credit facilities, are being amortized over the related lives. At December 31, 2017, $23.7 million of the deferred financing fees remain unamortized, $0.5 million of which is included in “Prepaid and other assets,” $1.3 million of which is included in “Other non-current assets” and $21.9 million of which is grouped and presented as part of “Long-term debt” on the Consolidated Statement of Financial Condition. At December 31, 2017 and 2016, the fair market value of the Company’s debt obligations was $2,231.1 million and $2,192.5 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, which are based on one or more quoted prices in markets that are not considered to be active or for which all significant inputs are observable, either directly or indirectly. 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. Derivatives and Hedging Activities. The Company is exposed to certain risks arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate, liquidity and credit risk primarily by managing the amount, sources, and duration of its debt funding and the use of derivative financial instruments. Specifically, the Company had previously entered into derivative financial instruments to manage exposures that arose from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates, and may do so again in the future. The Company’s derivative financial instruments were used to manage differences in the amount, timing and duration of the Company’s known or expected cash payments principally related to the Company’s borrowings. For the year ended December 31, 2017, the Company was not party to any interest rate swaps. 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, in certain cases, 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 economic 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 December 31, 2017, the Company had outstanding foreign currency forwards with a notional amount of $10.5 million that were not designated as hedges in qualifying hedging relationships. The following table presents the fair values of the Company’s derivative instruments and the location in which they are presented on the Company’s Consolidated Statements of Financial Condition: As of Consolidated Statements of December 31, December 31, (in thousands) Financial Condition Location 2017 2016 Non-designated hedging instruments: Asset derivatives: Foreign exchange contracts Prepaid and other assets $ - $ 27 Liability derivatives: Foreign exchange contracts Other accrued liabilities $ (118 ) $ (124 ) The following tables present the effect of the Company’s financial derivatives and the location in which they are presented on the Company’s Consolidated Statements of Financial Condition and Consolidated Statements of Income: Amount of Gain or (Loss) Recognized in Income on Derivatives for the Derivatives Not Designated as Location of Gain or Years Ended Hedging Instruments (Loss) Recognized December 31, December 31, December 31, (in thousands) in Income on Derivatives 2017 2016 2015 Foreign exchange contracts Other expense (income) $ (1,847 ) $ 1,566 $ 366 Gain on sale of investment During the year ended December 31, 2015, MSCI sold an investment accounted for under the cost method and recognized a $6.3 million gain. During the year ended December 31, 2017, MSCI recognized an additional $0.8 million gain upon final settlement of the amounts held in escrow related to this sale. These gains are included within the “Other expense (income), net” in the Consolidated Statements of Income.

Property, Equipment and Leaseho

Property, Equipment and Leasehold Improvements	12 Months Ended
	Dec. 31, 2017
Property Plant And Equipment [Abstract]
Property, Equipment and Leasehold Improvements	5. PROPERTY, EQUIPMENT AND LEASEHOLD IMPROVEMENTS Property, equipment and leasehold improvements at December 31, 2017 and 2016 consisted of the following: As of Estimated December 31, December 31, Useful 2017 2016 (in thousands) Computer & related equipment 2 $ 200,592 $ 162,306 Furniture & fixtures 7 years 10,591 9,724 Leasehold improvements 1 to 21 years 51,128 49,442 Work-in-process — 3,406 10,954 Subtotal 265,717 232,426 Accumulated depreciation and amortization (171,280 ) (136,841 ) Property, equipment and leasehold improvements, net $ 94,437 $ 95,585 Depreciation and amortization expense of property, equipment and leasehold improvements was $35.4 million, $34.3 million and $30.9 million for the years ended December 31, 2017, 2016 and 2015, respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	6. GOODWILL AND INTANGIBLE ASSETS Goodwill The change to the Company’s goodwill was as follows: (in thousands) Index Analytics All Other Total Goodwill at December 31, 2015 $ 1,208,454 $ 302,551 $ 54,616 $ 1,565,621 Changes to goodwill — 60 (1) (110 ) (2) (50 ) Foreign exchange translation adjustment (6,006 ) — (3,715 ) (9,721 ) Goodwill at December 31, 2016 $ 1,202,448 $ 302,611 $ 50,791 $ 1,555,850 Foreign exchange translation adjustment 2,952 — 1,819 4,771 Goodwill at December 31, 2017 $ 1,205,400 $ 302,611 $ 52,610 $ 1,560,621 (1) Reflects the final working capital adjustment payment made during the year ended December 31, 2016 to complete the acquisition of the Insignis business (“Insignis”). (2) Reflects the value disposed in the sale of the Real Estate occupiers business. Through the year ended December 31, 2017, the Company has never recognized an impairment of goodwill on its consolidated financial statements. Intangible Assets Amortization expense related to intangible assets for the years ended December 31, 2017, 2016 and 2015, was $44.5 million, $47.0 million and $46.9 million, respectively. The gross carrying and accumulated amortization amounts related to the Company’s identifiable intangible assets were as follows: As of Estimated December 31, December 31, Useful Lives 2017 2016 (in thousands) Gross intangible assets: Customer relationships 5 to 21 years $ 361,199 $ 361,199 Trademarks/trade names 5 to 21.5 years 223,382 223,382 Technology/software 3 to 8.5 years 225,407 210,013 Proprietary data 13 years 28,627 28,627 Covenant not to compete 2 years - 1,225 Subtotal 838,615 824,446 Foreign exchange translation adjustment (9,167 ) (13,946 ) Total gross intangible assets $ 829,448 $ 810,500 Accumulated amortization: Customer relationships $ (189,100 ) $ (166,923 ) Trademarks/trade names (116,691 ) (105,077 ) Technology/software (193,095 ) (184,290 ) Proprietary data (10,352 ) (8,571 ) Covenant not to compete - (1,089 ) Subtotal (509,238 ) (465,950 ) Foreign exchange translation adjustment 1,626 3,090 Total accumulated amortization $ (507,612 ) $ (462,860 ) Net intangible assets: Customer relationships $ 172,099 $ 194,276 Trademarks/trade names 106,691 118,305 Technology/software 32,312 25,723 Proprietary data 18,275 20,056 Covenant not to compete - 136 Subtotal 329,377 358,496 Foreign exchange translation adjustment (7,541 ) (10,856 ) Total net intangible assets $ 321,836 $ 347,640 Estimated amortization expense for succeeding years is presented below: Years Ending December 31, Amortization Expense (in thousands) 2018 $ 45,526 2019 43,593 2020 41,583 2021 38,488 2022 35,730 Thereafter 116,916 Total $ 321,836

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Employee Benefits	7. EMPLOYEE BENEFITS The Company sponsors a 401(k) plan for eligible U.S. employees and defined contribution and defined benefit pension plans that cover substantially all of its non-U.S. employees. For the years ended December 31, 2017, 2016 and 2015, costs relating to 401(k), pension and post-retirement benefit expenses were $22.5 million, $21.6 million and $23.1 million, respectively. Amounts included in cost of revenues for the years ended December 31, 2017, 2016 and 2015 were $10.6 million, $9.5 million and $10.7 million, respectively. Amounts included in selling and marketing for the years ended December 31, 2017, 2016 and 2015 were $6.7 million, $6.7 million and $6.8 million, respectively. Amounts included in research and development for the years ended December 31, 2017, 2016 and 2015 were $3.8 million, $4.0 million and $4.0 million, respectively. Amounts included in general and administrative for the years ended December 31, 2017, 2016 and 2015 were $1.5 million, $1.3 million and $1.6 million, respectively. 401(k) and Other Defined Contribution Plans. Eligible employees may participate in the MSCI 401(k) plan (or any other regional defined contribution plan sponsored by MSCI) immediately upon hire. Eligible employees receive 401(k) and other defined contribution plan matching contributions, which are subject to vesting and certain other limitations. The Company’s expenses associated with the 401(k) plan and other defined contribution plans for the years ended December 31, 2017, 2016 and 2015 were $19.2 million, $17.6 million and $18.4 million, respectively. Net Periodic Benefit Expense. Net periodic benefit expense incurred by the Company related to defined benefit pension plans was $3.3 million, $4.0 million and $4.7 million for the years ended December 31, 2017, 2016 and 2015, respectively. The Company uses a measurement date of December 31 to calculate obligations under its pension and postretirement plans. As of December 31, 2017 and 2016, the Company carried a net liability of $22.0 million and $18.4 million, respectively, in “Other non-current liabilities” on the Consolidated Statement of Financial Condition related to its future pension obligations. The fair value of the defined benefit plan assets were $20.6 million and $17.5 million at December 31, 2017 and 2016, respectively.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Shareholders' Equity	8. SHAREHOLDERS’ EQUITY This note reflects the share repurchases and related activity as well as share-based compensation activity recognized by the Company, including the amounts recognized in both continuing operations and discontinued operations for all periods referenced. Return of capital 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 was increased to $850.0 million on September 17, 2014 (the “2014 Repurchase Program”). On October 14, 2015, the Company exhausted the $850.0 million share repurchase authorization under the 2014 Repurchase Program. On September 18, 2014, as part of the 2014 Repurchase Program, the Company entered into an ASR agreement to initiate share repurchases aggregating $300.0 million (the “September 2014 ASR Agreement”). As a result of the September 2014 ASR Agreement, the Company received approximately 4.5 million shares of MSCI’s common stock on September 19, 2014 and received approximately 1.2 million shares of MSCI’s common stock on May 21, 2015 for a combined average price of $52.79 per share. On June 2, 2015, the Company began purchasing shares of its common stock in the open market in accordance with SEC Rule 10b5-1. During October 2015, the Company completed the $850.0 million repurchase authorization under the 2014 Repurchase Program. On October 28, 2015, the Board of Directors approved a new stock repurchase program authorizing the purchase of up to $1.0 billion worth of shares of MSCI’s common stock (the “2015 Repurchase Program”). On October 26, 2016, the Board of Directors approved an additional stock repurchase program authorizing the purchase of up to $750.0 million worth of shares of our common stock (together with the $330.3 million remaining authorization under the 2015 Repurchase Program, the “2016 Repurchase Program”). Share repurchases made pursuant to the 2016 Repurchase Program may take place 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 or terminated by the Board of Directors at any time without prior notice. As of December 31, 2017, there was $733.1 million of available authorization remaining under the 2016 Repurchase Program. The following table provides information with respect to repurchases of the Company’s common stock pursuant to open market repurchases: Year Ended Average Price Paid Per Share Total Number of Shares Repurchased Dollar Value of Shares Repurchased (in thousands, except per share data) December 31, 2015 $ 62.63 10,710 $ 670,824 December 31, 2016 $ 73.71 10,303 $ 759,427 December 31, 2017 $ 87.96 1,556 $ 136,899 The following table presents cash dividends declared and distributed per common share for the periods indicated: Dividends Per Share Declared Distributed Deferred 2017 (in thousands, except per share data) Three Months Ended March 31, $ 0.28 $ 25,769 $ 25,500 $ 269 Three Months Ended June 30, 0.28 25,710 25,444 266 Three Months Ended September 30, 0.38 34,768 34,403 365 Three Months Ended December 31, 0.38 34,745 34,448 297 Total $ 1.32 $ 120,992 $ 119,795 $ 1,197 2016 Three Months Ended March 31, $ 0.22 $ 22,046 $ 21,889 $ 157 Three Months Ended June 30, 0.22 21,588 21,391 197 Three Months Ended September 30, 0.28 26,936 26,680 256 Three Months Ended December 31, 0.28 26,524 26,304 220 Total $ 1.00 $ 97,094 $ 96,264 $ 830 2015 Three Months Ended March 31, $ 0.18 $ 20,424 $ 20,411 $ 13 Three Months Ended June 30, 0.18 20,444 20,442 2 Three Months Ended September 30, 0.22 24,210 24,152 58 Three Months Ended December 31, 0.22 22,803 22,792 11 Total $ 0.80 $ 87,881 $ 87,797 $ 84 Common Stock The following table presents activity related to shares of common stock issued and repurchased for the periods indicated: Common Treasury Common Stock Issued Stock Outstanding Balance At December 31, 2014 126,637,390 (14,564,921 ) 112,072,469 Dividend payable/paid 802 (385 ) 417 Common stock issued and exercise of stock options 1,558,965 — 1,558,965 Shares withheld for tax withholding and exercises — (763,558 ) (763,558 ) Shares repurchased under stock repurchase programs — (11,856,169 ) (11,856,169 ) Shares issued to directors 3,032 (2,008 ) 1,024 Balance At December 31, 2015 128,200,189 (27,187,041 ) 101,013,148 Dividend payable/paid 892 (472 ) 420 Common stock issued and exercise of stock options 788,304 — 788,304 Shares withheld for tax withholding and exercises — (219,921 ) (219,921 ) Shares repurchased under stock repurchase programs — (10,303,047 ) (10,303,047 ) Shares issued to directors 6,959 (6,273 ) 686 Balance At December 31, 2016 128,996,344 (37,716,754 ) 91,279,590 Dividend payable/paid 156 — 156 Common stock issued and exercise of stock options 538,499 — 538,499 Shares withheld for tax withholding and exercises — (158,090 ) (158,090 ) Shares repurchased under stock repurchase programs — (1,556,313 ) (1,556,313 ) Shares issued to directors 8,857 (7,814 ) 1,043 Balance At December 31, 2017 129,543,856 (39,438,971 ) 90,104,885 Shared-Based Compensation The Company regularly issues share-based compensation to its employees and directors who are not employees of the Company. The accounting guidance for share-based compensation requires measurement of compensation cost for share-based awards at fair value and recognition of compensation cost over the service period, net of estimated forfeitures. In February 2018, the Company granted a portion of its employees awards in the form of RSUs and MSUs. The total number of units granted was 211,144. The aggregate fair value of the awards was $26.6 million, of which approximately $2.4 million had been expensed in the year ended December 31, 2017 in relation to awards granted to retirement eligible employees under the award terms. A portion of the awards granted consisted of RSUs vesting over a three-year period, with one-third vesting on each anniversary of the grant in 2019, 2020 and 2021. A smaller portion of the awards granted consisted of MSUs that will time-vest over a three year period and are subject to the achievement of the applicable absolute total shareholder return compounded annual growth rate and relative total shareholder return compounded annual growth rate performance metrics measured over a minimum three-year performance period. The performance period may also be extended for an additional period of six months only in the event that both of the performance metrics achieved by the Company are below specified threshold performance levels. For a small group of awards granted by the Company, all or a portion of the award may be cancelled in certain limited situations, including termination for cause, if employment is terminated before the end of the relevant restriction period. For the remainder of the awards granted by the Company, all or a portion of the award may be canceled if employment is terminated for certain reasons before the end of the relevant restriction period for non-retirement-eligible employees. In connection with awards under its equity-based compensation and benefit plans, the Company is authorized to use newly issued shares or certain shares of common stock held in treasury. The components of share-based compensation expense related to the awards to Company employees and directors who are not employees of the Company of restricted stock units and restricted stock awards (representing shares of common stock) and options to purchase shares of common stock, as applicable, are presented below: Years Ended December 31, December December 31, (in thousands) 2017 2016 2015 Deferred stock $ 37,921 $ 32,525 $ 27,549 Stock options — — (73 ) Total $ 37,921 $ 32,525 $ 27,476 The following table presents the amount of share-based compensation expense by category for the periods indicated: Years Ended December 31, December 31, December 31, (in thousands) 2017 2016 2015 Cost of revenues $ 9,707 $ 7,971 $ 6,909 Selling and marketing 11,355 9,526 6,564 Research and development 3,477 2,970 2,823 General and administrative 13,382 12,058 11,180 Total share-based compensation expense $ 37,921 $ 32,525 $ 27,476 There was no share-based compensation expense included in “Income (loss) from discontinued operations, net of income taxes” in the Consolidated Statement of Income for the years ended December 31, 2017, 2016 and 2015. The tax benefits for share-based compensation expense related to deferred stock and stock options granted to Company employees and to directors who are not employees of the Company were $5.5 million, $7.4 million and $15.3 million for the years ended December 31, 2017, 2016 and 2015, respectively. As of December 31, 2017, $29.9 million of compensation cost related to MSCI unvested share-based awards granted to the Company’s employees and to directors who are not employees of the Company had not yet been recognized. The unrecognized compensation cost relating to unvested stock-based awards expected to vest will be recognized primarily over the next one to three years. In connection with awards under its equity-based compensation and benefit plans, the Company is authorized to issue shares of common stock. As of December 31, 2017, 7.3 million shares of common stock were available for future grants under these plans. Deferred Stock Awards. Certain Company employees have been granted deferred stock awards pursuant to a share-based compensation plan. The plan provides for the deferral of a portion of certain employees’ discretionary compensation with awards made in the form of RSUs, PSUs and MSUs (together, the “Deferred Stock Awards”). Recipients of RSUs, PSUs and MSUs generally have rights to receive dividend equivalents that are subject to vesting. The Company reports the target number of PSUs and MSUs granted unless it has determined, based on the actual achievement of performance measures, that an employee will receive a different amount of shares underlying the PSUs and MSUs, in which case the Company reports the amount of shares employees are likely to receive. The following table presents activity concerning the Company’s vested and unvested deferred stock awards applicable to its employees (share data in thousands) for the period indicated: Weighted Average Grant Number of Date Fair For the Year Ended December 31, 2017 Shares Value Vested and unvested deferred stock awards at December 31, 2016 1,507 $ 61.82 Granted 302 $ 88.01 Conversion to common stock (351 ) $ 56.83 Canceled (39 ) $ 66.25 Vested and unvested deferred stock awards at December 31, 2017 (1) 1,419 $ 68.50 (1) As of December 31, 2017, 1,366 restricted stock units and restricted stock awards, with a weighted average price of $68.35, were vested or expected to vest. The total fair value of Deferred Stock Awards held by the Company’s employees that converted to MSCI common stock during the years ended December 31, 2017, 2016 and 2015 was $30.3 million, $39.4 million and $34.1 million, respectively. The following table presents activity concerning the Company’s unvested deferred stock awards related to its employees (share data in thousands): Weighted Average Grant Number of Date Fair For the Year Ended December 31, 2017 Shares Value Unvested deferred stock awards at December 31, 2016 1,207 $ 62.89 Granted 277 $ 88.27 Vested (279 ) $ 58.06 Canceled (39 ) $ 66.25 Unvested deferred stock awards at December 31, 2017 1,166 $ 69.96 Unvested deferred stock awards expected to vest 1,113 $ 69.84 Stock Option Awards. No stock options were issued during the years ended December 31, 2017, 2016 and 2015. The following table presents activity concerning MSCI stock options granted to the Company’s employees for the year ended December 31, 2017 (option data and dollar values in thousands, except exercise price): Weighted Weighted Average Number Average Remaining Aggregated of Exercise Life Intrinsic For the Year Ended December 31, 2017 Options Price (Years) Value Options outstanding at December 31, 2016 269 $ 24.06 2.22 N/A Granted or assumed — $ — N/A N/A Forfeited — $ — N/A N/A Conversion to common stock (124 ) $ 21.24 N/A N/A Options outstanding and exercisable at December 31, 2017 145 $ 26.47 2.11 $ 14,519 All outstanding stock options as of December 31, 2017 are vested and exercisable. The following table presents information relating to the Company’s outstanding and exercisable stock options as of December 31, 2017 (number of options outstanding and aggregate intrinsic value data in thousands): As of December 31, 2017 Options Outstanding Weighted Average Average Aggregate Number Exercise Remaining Intrinsic Range of Exercise Prices Outstanding Price Life (Years) Value $15.18 to $16.48 38 $ 16.47 1.15 $ 4,175 $20.45 to $24.11 16 $ 20.62 1.77 $ 1,733 $ 25.64 41 $ 25.64 2.11 $ 4,139 $ 36.70 50 $ 36.70 2.95 $ 4,472 Total 145 $ 14,519 The intrinsic value of the stock options exercised by the Company’s employees during the years ended December 31, 2017, 2016 and 2015 was $10.9 million, $11.3 million and $37.3 million, respectively.

Reclassifications out of Accumu

Reclassifications out of Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Reclassifications out of Accumulated Other Comprehensive Income (Loss)	9. RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) As required by ASC Subtopic 220-10, “ Comprehensive Income—Overall Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (1) Details about Accumulated Other Amount Reclassified from Accumulated Affected Comprehensive Income (Loss) Components Other Comprehensive Income (Loss) Consolidated Statements of Income Years Ended December 31, December 31, December 31, 2017 2016 2015 (in Defined benefit pension plans Amount recognized as a component of net periodic benefit expense for curtailments and settlements $ (281 ) $ (261 ) $ (563 ) 77 73 153 Provision for income taxes Total reclassifications for the period, net of tax $ (204 ) $ (188 ) $ (410 ) (1) Amounts in parentheses indicate expenses or losses moved to the Consolidated Statements of Income.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	10. INCOME TAXES The provision for income taxes (benefits) by taxing jurisdiction consisted of: Years Ended December 31, December 31, December 31, 2017 2016 2015 (in thousands) Current U.S. federal $ 133,250 $ 93,071 $ 85,540 U.S. state and local 16,312 16,363 22,108 Non U.S. 32,267 32,616 22,156 181,829 142,050 129,804 Deferred U.S. federal (12,502 ) (13,010 ) (10,546 ) U.S. state and local (2,119 ) (2,235 ) 1,460 Non U.S. (4,281 ) (1,722 ) (1,202 ) (18,902 ) (16,967 ) (10,288 ) Provision for income taxes from continuing operations $ 162,927 $ 125,083 $ 119,516 Provision for income taxes from discontinued operations $ — $ — $ 6,390 The following table reconciles the provision to the U.S. federal statutory income tax rate for income from continuing operations: Years Ended December 31, December 31, December 31, 2017 2016 2015 U.S. federal statutory income tax rate 35.00 % 35.00 % 35.00 % U.S. state and local income taxes, net of U.S. federal income tax benefits 1.84 % 2.38 % 4.44 % Change in tax rates applicable to non-U.S. earnings (7.60 %) (3.73 %) (2.73 %) Domestic tax credits and incentives (0.24 %) (0.26 %) (2.62 %) Net tax charge related to Tax Reform 7.40 % — % — % Excess Stock Based Compensation (1.25 %) — % — % Other (0.25 %) (0.98 %) 0.10 % Effective income tax rate 34.90 % 32.41 % 34.19 % On December 22, 2017 the U.S. government enacted Tax Reform. Tax Reform significantly revises the U.S. corporate income tax by, among other things, lowering U.S. corporate income tax rates, implementing a territorial tax system and imposing a one-time tax on deemed repatriation of historic earnings and profits (“E&P”) of foreign subsidiaries (the “Toll Charge”). The provisions of Tax Reform will impact the Company for the annual reporting periods, including interim periods within those periods, beginning after December 31, 2017 as well as during the three months ended December 31, 2017. The U.S. federal income tax rate reduction was effective as of January 1, 2018. Pursuant to SAB 118 and given the amount and complexity of the changes in tax law resulting from Tax Reform, the Company has not finalized the accounting for the income tax effects of Tax Reform. This includes the provisional amounts recorded related to the Toll Charge, the remeasurement of deferred taxes and the change in the Company’s indefinite reinvestment assertion. The impact of Tax Reform may differ from this estimate, possibly materially, during the one-year measurement period due to, among other things, further refinement of the Company’s calculations as it completes its tax returns for the fiscal year ended December 31, 2017, changes in interpretations and assumptions the Company has made and ongoing guidance and accounting interpretations that may be issued as a result of Tax Reform. The Company’s provisional accounting for the effects of Tax Reform resulted in a net charge of $34.5 million in the provision for income taxes for MSCI that primarily included an estimated tax charge of approximately $47.5 million related to the Toll Charge and an estimated tax charge of approximately $16.0 million related to a change in assertion that those profits were permanently reinvested overseas as of December 31, 2017, partially offset by an estimated tax benefit of approximately $29.0 million related to the revaluation of deferred taxes at the now lower statutory corporate rate. The Toll Charge is based on the Company’s E&P of foreign subsidiaries for which the Company had not previously recognized U.S. income taxes. The total estimated Toll Charge of $47.5 million was recognized discretely in the year ended December 31, 2017. As of December 31, 2017, $43.6 million of the Toll Charge was held in “Other non-current liabilities” on the Consolidated Statement of Financial Condition as the amounts are not payable until after December 31, 2018. The Company has not yet finalized its calculation of the total E&P for its foreign subsidiaries. As of December 31, 2017, the Company no longer considers available cash balances to be indefinitely reinvested and recorded an estimated tax charge of $16.0 million related to foreign withholding taxes during the year ended December 31, 2017. However, the Company is continuing to assess its intentions related to its indefinite reinvestment assertion for future periods. Deferred income taxes reflect the net tax effects of temporary differences between the financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when such differences are expected to reverse. Significant components of the Company’s deferred tax assets and liabilities as of December 31, 2017 and 2016, were as follows: As of December 31, December 31, 2017 2016 (in thousands) Deferred tax assets: Employee compensation and benefit plans $ 19,646 $ 27,914 Deferred rent 5,308 7,869 Pension 1,520 1,965 Unearned revenue 853 1,322 Loss carryforwards - non-current 18,105 27,616 Other 1,435 558 Subtotal 46,867 67,244 Less: valuation allowance (11,575 ) (17,807 ) Total deferred tax assets $ 35,292 $ 49,437 Deferred tax liabilities: Intangible assets $ (73,634 ) $ (121,900 ) Investment in foreign subsidiaries (16,108 ) — Property, equipment and leasehold improvements, net (11,564 ) (12,073 ) Total deferred tax liabilities $ (101,306 ) $ (133,973 ) Net deferred tax liabilities $ (66,014 ) $ (84,536 ) As presented in the table above, the Company has certain loss carryforward items. The tax value of the capital loss carryforward is $10.6 million which is set to expire in 2019. There is a full valuation allowance against this item. The tax value of the United States portion of the net operating loss carryforwards is $6.3 million which is subject to an annual limitation on utilization and will begin to expire in 2020. There is a valuation allowance against state tax losses of $0.4 million. As of December 31, 2017, the tax value of foreign net operating loss carryforwards was $1.3 million with a related valuation allowance of $0.6 million. The following table presents changes in the Company’s deferred tax asset valuation allowance for the periods indicated: Years Ended December 31, December 31, December 31, 2017 2016 2015 (in thousands) Beginning balance $ 17,807 $ 21,052 $ 21,232 Additions charged to cost and expenses 324 1,862 — Additions charged to other accounts — — — Deductions (6,556 ) (5,107 ) (180 ) Ending balance $ 11,575 $ 17,807 $ 21,052 The following table presents the components of income before provision for income taxes generated by domestic or foreign operations for the periods indicated: Years Ended December 31, December 31, December 31, 2017 2016 2015 (in thousands) Domestic $ 283,779 $ 263,536 $ 282,764 Foreign (1) 183,120 122,402 66,790 Total income before provision for income taxes $ 466,899 $ 385,938 $ 349,554 (1) Foreign income before provision for income taxes is defined as income generated from operations located outside the U.S., which includes income from foreign branches of U.S. companies. Cumulative earnings attributable to foreign subsidiaries were $450.7 million, $341.6 million and $224.8 million for the years ended December 31, 2017, 2016, and 2015, respectively. The Company has recorded a $16.0 million charge to provision for income taxes related to foreign withholding taxes that would be payable upon repatriation. 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 are remeasured. It is reasonably possible that significant changes in the balance of unrecognized tax benefits may occur within the next 12 months. At this time, however, it is not possible to reasonably estimate the expected change to the total amount of unrecognized tax benefits and the impact on the effective tax rate over the next 12 months. The Company believes the resolution of tax matters will not have a material effect on the Consolidated Statement of Financial Condition of the Company, although a resolution could have a material impact on the Company’s Consolidated Statement of Income for a particular future period and on the Company’s effective tax rate for any period in which such resolution occurs. The following table presents a reconciliation of the beginning and ending amount of the gross unrecognized tax benefits, excluding interest and penalties, for the years ended December 31, 2017, 2016 and 2015: Years Ended December 31, December 31, December 31, Gross unrecognized tax benefits 2017 2016 2015 (in thousands) Beginning balance $ 7,936 $ 8,692 $ 6,525 Increases based on tax positions related to the current period 3,389 575 536 Increases based on tax positions related to prior periods 519 135 2,131 Decreases based on tax positions related to prior periods (6 ) (3 ) (500 ) Decreases related to settlements with taxing authorities (1,152 ) (1,463 ) — Decreases related to a lapse of applicable statute of limitations (664 ) — — Ending balance $ 10,022 $ 7,936 $ 8,692 The total amount of unrecognized tax benefits was $9.4 million, net of federal benefit of state issues, competent authority and foreign tax credit offsets, as of December 31, 2017, which, if recognized, would favorably affect the effective tax rate in future periods. The Company recognizes the accrual of interest and penalties related to unrecognized tax benefits in the “Provision for income taxes” in the Consolidated Statement of Income. For the year ended December 31, 2017, the Company recognized $0.2 million of interest in the Consolidated Statement of Income with respect to unrecognized tax benefits. No significant penalties were recognized in the Consolidated Statement of Income for the year ended December 31, 2017. The amount of accrued interest, which includes interest related to uncertain tax positions and accrued income tax expense, recorded on the Consolidated Statement of Financial Condition as of December 31, 2017 was $0.9 million. The Company is under examination by the IRS and other tax authorities in certain jurisdictions, including foreign jurisdictions, such as India, and states in which the Company has significant operations, such as New York. The tax years currently under examination vary by jurisdiction but include years ranging from 2006 through 2016. 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 and 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 examinations. 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.

Acquisitions And Dispositions

Acquisitions And Dispositions	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Acquisitions And Dispositions	11. ACQUISITIONS AND DISPOSITIONS The acquisition method of accounting is based on ASC Subtopic 805-10, “ Business Combinations, Fair Value Measurements and Disclosures, Acquisition of Insignis On October 16, 2015, the Company completed the purchase of Insignis for $6.5 million through its subsidiary InvestorForce. Insignis is a financial data provider, including data on positions, transactions and complex instruments such as exchange-traded futures and options, OTC swaps and foreign exchange spot and forward contracts. The purchase price allocations for the Insignis acquisition were $4.2 million for goodwill, $2.2 million for identifiable intangible assets and $0.1 million for assets other than identifiable intangible assets. Disposition of Real Estate occupiers On August 1, 2016, MSCI completed the sale of its Real Estate occupiers business. 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 and completed the sale on April 30, 2014. The results of operations from ISS are reflected in “Income (loss) from discontinued operations, net of income taxes” in the Consolidated Statements of Income. The year ended December 31, 2015 reflects the impact of out-of-period income tax charges associated with the tax obligations triggered upon the sale of ISS.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment Information	12. SEGMENT INFORMATION ASC Subtopic 280-10, “ Segment Reporting, The CODM measures and evaluates reportable segments based on segment operating revenues as well as Adjusted EBITDA and other measures. The Company excludes the following items from segment Adjusted EBITDA: income (loss) from discontinued operations, net of income taxes, provision for income taxes, other expense (income), net, depreciation and amortization of property, equipment and leasehold improvements, amortization of intangible assets and certain transactions or adjustments that the CODM does not consider for the purposes of making decisions to allocate resources among segments or to assess segment performance. Although these amounts are excluded from segment Adjusted EBITDA, they are included in reported consolidated net income and are included in the reconciliation that follows. The Company’s computation of segment Adjusted EBITDA may not be comparable to other similarly titled measures computed by other companies because all companies do not calculate segment Adjusted EBITDA in the same fashion. Revenues and expenses directly associated with each segment are included in determining its operating results. Other expenses that are not directly attributable to a particular segment are based upon allocation methodologies, including time estimates, headcount, sales targets, data center consumption and other relevant usage measures. Due to the integrated structure of our business, certain costs incurred by one segment may benefit other segments. A segment may use the content and data produced by another segment without incurring an arm’s-length intersegment charge. The CODM does not review any information regarding total assets on an operating segment basis. Operating segments do not record intersegment revenue, and, accordingly, there is none to be reported. The accounting policies for segment reporting are the same as for MSCI as a whole. The Company has four operating segments: Index, Analytics, ESG and Real Estate. The Index operating segment is primarily a provider of equity indexes. The indexes are used in many areas of the investment process, including index-linked product creation and performance benchmarking, as well as portfolio construction and rebalancing and asset allocation. The Analytics operating segment offers risk management, performance attribution and portfolio management content, applications and services that provide clients with an integrated view of risk and return and an analysis of market, credit, liquidity and counterparty risk across all major asset classes, spanning short, medium and long-term time horizons. Clients access Analytics content through MSCI’s own proprietary applications and APIs, or through third party applications or directly on their own platforms. The Analytics operating segment also provides various managed services to help clients operate more efficiently as well as address the needs of certain specialized areas of the investment community by providing a reporting service and performance reporting tools to institutional consultants and investors in hedge funds. The ESG operating segment offers products and services that help institutional investors understand how environmental, social and governance factors can impact the long-term risk of their investments. In addition, MSCI ESG Research data and ratings are used in the construction of equity and fixed income indexes to help institutional investors more effectively benchmark ESG investment performance, issue index-based investment products, as well as manage, measure and report on ESG mandates. The Real Estate operating segment includes research, reporting and benchmarking offerings that provide real estate performance analysis for funds, investors and managers. Real Estate performance and risk analytics range from portfolio to property-specific analysis. The Real Estate operating segment also provides business intelligence to real estate owners, managers, developers and brokers worldwide. During the year ended December 31, 2016, the Company disposed of the Real Estate occupiers business and recorded an immaterial gain on the disposition which was recorded in “Other expense (income),” in the Consolidated Statement of Income. The operating segments of ESG and Real Estate do not individually meet the segment reporting thresholds and have been combined and presented as part of All Other for disclosure purposes. The following table presents operating revenue by reportable segment for the periods indicated: Years Ended December 31, December 31, December 31, 2017 2016 2015 (in thousands) Operating revenues Index $ 718,959 $ 613,551 $ 558,964 Analytics 458,269 448,353 433,424 All Other 96,944 88,765 82,625 Total $ 1,274,172 $ 1,150,669 $ 1,075,013 The following table presents segment profitability and a reconciliation to net income for the periods indicated: Years Ended December 31, December 31, December 31, 2017 2016 2015 (in thousands) Index Adjusted EBITDA $ 522,043 $ 431,478 $ 392,987 Analytics Adjusted EBITDA 125,349 128,507 95,468 All Other Adjusted EBITDA 11,783 9,472 (6,758 ) Total operating segment profitability 659,175 569,457 481,697 Amortization of intangible assets 44,547 47,033 46,910 Depreciation and amortization of property, equipment and leasehold improvements 35,440 34,320 30,889 Operating income 579,188 488,104 403,898 Other expense (income), net 112,289 102,166 54,344 Provision for income taxes 162,927 125,083 119,516 Income from continuing operations 303,972 260,855 230,038 Income (loss) from discontinued operations, net of income taxes — — (6,390 ) Net income $ 303,972 $ 260,855 $ 223,648 Revenue by geography is based on the shipping address of the ultimate customer utilizing the product. The following table presents revenue by geographic area for the periods indicated: Years Ended December 31, December 31, December 31, (in thousands) 2017 2016 2015 Revenues Americas: United States $ 622,132 $ 556,777 $ 519,429 Other 48,139 45,185 41,552 Total Americas 670,271 601,962 560,981 Europe, the Middle East and Africa ("EMEA"): United Kingdom 193,831 175,749 166,019 Other 250,267 229,010 215,192 Total EMEA 444,098 404,759 381,211 Asia & Australia: Japan 54,351 52,161 45,371 Other 105,452 91,787 87,450 Total Asia & Australia 159,803 143,948 132,821 Total $ 1,274,172 $ 1,150,669 $ 1,075,013 Long-lived assets consist of property, equipment, leasehold improvements, goodwill and intangible assets, net of accumulated depreciation and amortization. The following table presents long-lived assets by geographic area on the dates indicated: As of December 31, December 31, 2017 2016 (in thousands) Long-lived assets Americas: United States $ 1,847,605 $ 1,876,366 Other 1,685 1,543 Total Americas 1,849,290 1,877,909 EMEA: United Kingdom 94,782 89,466 Other 22,394 23,780 Total EMEA 117,176 113,246 Asia & Australia: Japan 432 357 Other 9,996 7,563 Total Asia & Australia 10,428 7,920 Total $ 1,976,894 $ 1,999,075

Quarterly Results of Operations

Quarterly Results of Operations	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations	13. QUARTERLY RESULTS OF OPERATIONS (unaudited): 2017 2016 First Second Third Fourth First Second Third Fourth Quarter Quarter Quarter Quarter Quarter Quarter Quarter Quarter (in thousands, except per share data) Operating revenues $ 301,207 $ 316,089 $ 322,097 $ 334,779 $ 278,828 $ 290,596 $ 288,433 $ 292,812 Cost of revenues 67,521 68,595 68,491 69,306 63,172 62,130 62,986 63,819 Selling and marketing 43,014 41,594 44,918 47,771 41,689 41,854 41,514 41,609 Research and development 18,977 18,203 17,983 20,721 18,928 18,566 18,750 18,960 General and administrative 21,004 21,448 22,103 23,348 21,890 22,019 21,859 21,467 Amortization of intangible assets 11,251 11,122 10,614 11,560 11,840 11,943 11,752 11,498 Depreciation and amortization of property, equipment and leasehold improvements 8,838 9,159 9,325 8,118 8,168 8,393 8,312 9,447 Total operating expenses 170,605 170,121 173,434 180,824 165,687 164,905 165,173 166,800 Operating income 130,602 145,968 148,663 153,955 113,141 125,691 123,260 126,012 Interest income (932 ) (1,310 ) (1,835 ) (2,237 ) (621 ) (585 ) (799 ) (901 ) Interest expense 29,024 29,027 29,020 29,027 22,904 22,918 26,790 29,039 Other expense (income) 885 740 675 205 81 2,814 (253 ) 779 Other expense (income), net 28,977 28,457 27,860 26,995 22,364 25,147 25,738 28,917 Income from continuing operations before provision for income taxes 101,625 117,511 120,803 126,960 90,777 100,544 97,522 97,095 Provision for income taxes 28,674 36,245 35,650 62,358 30,410 33,587 32,241 28,845 Net income $ 72,951 $ 81,266 $ 85,153 $ 64,602 $ 60,367 $ 66,957 $ 65,281 $ 68,250 Earnings per basic common share $ 0.80 $ 0.90 $ 0.94 $ 0.72 $ 0.61 $ 0.69 $ 0.69 $ 0.73 Earnings per diluted common share $ 0.80 $ 0.89 $ 0.93 $ 0.70 $ 0.60 $ 0.69 $ 0.68 $ 0.73 Weighted average shares outstanding used in computing per share data Basic 90,708 90,404 90,112 90,130 99,425 96,412 94,823 93,327 Diluted 91,624 91,708 91,868 92,467 99,998 96,888 95,473 93,845

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	14. SUBSEQUENT EVENTS On January 30, 2018, the Board of Directors of the Company declared a quarterly dividend of $0.38 per share of common stock to be paid on March 15, 2018 to shareholders of record as of the close of trading on February 16, 2018. Subsequent to the year ended December 31, 2017 and through February 16, 2018, the Company repurchased an additional 0.4 million shares of common stock at an average price of $137.06 per share for a total value of $54.5 million.

Introduction and Basis of Pre23

Introduction and Basis of Presentation (Policies)	12 Months Ended
	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of MSCI Inc. and its wholly-owned subsidiaries. The Company’s policy is to consolidate all entities in which it owns more than 50% of the outstanding voting stock unless it does not control the entity. It is also the Company’s policy to consolidate any variable interest entity for which the Company is the primary beneficiary, as required by the Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification (“ASC”) Subtopic 810-10, “ Consolidations.” The Company’s operating expenses are grouped and presented in the following activity categories: cost of revenues, selling and marketing, research and development and general and administrative. Costs are assigned to these activity categories based on the nature of the expense to which they directly relate, or, when not directly attributable, based on an allocation method that considers the type of effort related to such activities. Cost of revenues consists of costs related to the production and servicing of the Company’s products and services and primarily includes related information technology costs, including data center, platform and infrastructure costs; costs to acquire, produce and maintain market data information; costs of research to support, maintain existing products; costs of product management teams; costs of client service and consultant teams to support customer needs; as well as other support costs directly attributable to the cost of revenues including certain human resources, finance and legal costs. Selling and marketing expenses consist of costs associated with acquiring new clients or selling new products or product renewals to existing clients and primarily includes the costs of MSCI’s sales force and marketing teams as well as costs incurred in other groups associated with acquiring new business, including product management, research, technology and sales operations. Research and development expenses consist of costs to develop new or enhance existing products and the costs to develop new or improved technology and service platforms for the delivery of MSCI’s products and services and primarily includes the costs of development, research, product management, project management and the technology support associated with these efforts. General and administrative expenses consist of costs primarily related to finance operations, human resources, office of the CEO, legal, corporate technology, corporate development and certain other administrative costs that are not directly attributed, but are instead allocated, to a product or service.
Basis of Financial Statements and Use of Estimates	Basis of Financial Statements and Use of Estimates The Company’s 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 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, impairment of long-lived assets, accrued compensation, income taxes and other matters that affect the consolidated financial statements and related disclosures. The Company believes that estimates used in the preparation of these consolidated financial statements are reasonable; however, actual results could differ materially from these estimates. Inter-company balances and transactions are eliminated in consolidation.
Revenue Recognition	Revenue Recognition The Company applies SEC Staff Accounting Bulletin No. 104 (“SAB 104”), “ Revenue Recognition, • the Company has persuasive evidence of a legally binding arrangement, • delivery has occurred, • client fee is deemed fixed or determinable, and • collection is reasonably assured. When a sales arrangement requires the delivery of more than one product and service, revenue is recognized pursuant to the requirements of ASC Subtopic 605-25, “ Revenue Arrangements with Multiple Deliverables. • the delivered items have value to the client on a standalone basis, which means they can be sold separately by any vendor or the client could resell the delivered items on a standalone basis; and • if the arrangement includes a general right of return relative to the delivered items, delivery or performance of the undelivered items is considered probable and substantially in the control of the vendor. The Company has signed contracts or agreements with substantially all clients that set forth the fees to be paid for its products and services. Further, the Company regularly assesses the receivable balances for each client for collectability. The Company’s application service license arrangements generally do not include acceptance provisions, which generally allow a client to test the solution for a defined period of time before committing to the license. If a license agreement includes an acceptance provision, the Company does not recognize subscription revenues until the earlier of the receipt of a written client acceptance or, if not notified by the client that it is cancelling the license agreement, the expiration of the acceptance period. The Company’s subscription agreements for hosted services include provisions that, among other things, allow clients, for no additional fee, to receive updates and modifications that may be made from time to time when and if available, for the term of the agreement, which is typically one year. These arrangements do not provide the client with the right to take possession of the application at any time. For sales arrangements with multiple deliverables, which may include application service subscription and professional services associated with implementation and other services, the Company evaluates each deliverable in these multiple-element arrangements to determine whether it represents a separate unit of accounting and allocates revenue accordingly, based on the Company’s best estimated sales price. In most cases, the Company recognizes revenues from subscription arrangements ratably over the term of the license agreement pursuant to the contract’s terms. The contracts state the terms under which these fees are to be calculated. The fees are recognized as the Company supplies the product and service to the client over the license period and are generally billed in advance, prior to the license start date. When implementation services are included, the Company recognizes revenues allocated to the subscription ratably from the date the application is put into production to the end of the license period. Revenues associated with implementation services are recognized ratably over the useful life of those services from the date the application is put into production. For products and services whose fees are based on estimated assets under management linked to the Company’s indexes, or contract values related to futures and options, the Company recognizes revenues based on estimates from independent third-party sources or the most recently reported information from the client. Revenues from subscription agreements for the receipt of periodic benchmark reports, digests, and other publications, which are most often associated with the Company’s real estate operating segment, are primarily recognized upon delivery of such reports or data updates. The Company’s software-related arrangements do not require significant modification or customization of any underlying software applications being licensed. Accordingly, the Company recognizes software revenues pursuant to the requirements of ASC Subtopic 985-605, “ Software—Revenue Recognition.” Software—Revenue Recognition,
Share-Based Compensation	Share-Based Compensation Certain of the Company’s employees have received share-based compensation under various compensation programs. The Company’s compensation expense reflects the fair value method of accounting for share-based payments under ASC Subtopic 718-10, “ Compensation—Stock Compensation. The fair value of MSCI restricted stock units (“RSUs”) is measured using the closing price of MSCI’s common stock on the date prior to grant. Restricted stock units subject to performance conditions (“PSUs”) are based on performance measures that impact the amount of shares that each recipient will receive upon vesting. The fair value of PSUs is measured using the closing price of MSCI’s common stock on the date prior to grant. Restricted stock units that are subject to the achievement of multi-year total shareholder return targets (“MSUs”) are performance awards with a market condition. The fair value of MSUs is determined using a Monte Carlo simulation model that creates a normal distribution of future stock prices, which is then used to value the awards based on their individual terms. The fair value of MSCI standard stock options is determined using the Black-Scholes valuation model and the single grant life method. Under the single grant life method, option awards with graded vesting are valued using a single weighted-average expected option life. The fair value of MSCI stock options that contain stock price contingencies is determined using a Monte Carlo simulation model. The Company recognizes the expense for an award granted to an employee who is not retirement-eligible utilizing the graded vesting method over the requisite service period. For all awards, the Company bases initial accruals of compensation cost on the estimated number of units for which the requisite service is expected to be rendered and, for PSUs, the performance targets expected to be achieved is also considered. If the estimated number of units or the number of units ultimately delivered changes from previous estimates, the cumulative effect on current and prior periods of a change is recognized in compensation cost in the period of the change. Because the probability of actual shares expected to be earned is reflected in the fair value of MSUs on the grant date, the expense to be recognized for these awards is not adjusted to reflect the actual shares earned. Based on interpretive guidance related to share-based compensation, the Company’s policy is to accrue the estimated cost of share-based awards that are granted to retirement-eligible employees over the course of the prior year in which they were earned rather than expensing the awards on the date of grant. A portion of the awards granted to retirement-eligible employees consisted of PSUs. For those PSUs, the Company bases initial accruals of compensation cost on the estimated number of units for which the requisite service is expected to be rendered. If the estimated number of units expected to convert changes from previous estimates based on the performance targets expected to be achieved, the cumulative effect of a change is recognized in compensation cost in the period of the change.
Research and Development	Research and Development The Company accounts for research and development costs in accordance with several accounting pronouncements, including ASC Subtopic 730-10, “ Research and Development The Company applies the provisions of ASC Subtopic 350-40, “ Internal Use Software For the year ended December 31, 2017, the Company capitalized $15.6 million of costs related to software developed for internal use in the Consolidated Statement of Financial Condition for the year ended December 31, 2017. For the year ended December 31, 2016, the Company capitalized $10.3 million of costs related to software developed for internal use in the Consolidated Statement of Financial Condition for the year ended December 31, 2016. Capitalized software development costs are amortized on a straight-line basis over the estimated useful life of the related product, which is typically three to five years, beginning with the date the software is placed into service. Costs incurred in the preliminary and post-implementation stages of MSCI’s products are expensed as incurred.
Income Taxes	Income Taxes Income tax expense is provided for using the asset and liability method, under which deferred tax assets and deferred tax liabilities are determined based on the temporary differences between the financial statement and income tax bases of assets and liabilities using currently enacted tax rates. The Company recognizes interest and penalties related to income tax matters within “Provision for income taxes” in the Consolidated Statement of Income. The Company regularly evaluates the likelihood of additional assessments in each of the taxing jurisdictions in which it is required to file income tax returns. The Company has recorded additional tax expense related to open tax years, which the Company’s management believes is adequate in relation to the potential for assessments. These amounts have been recorded in “Other non-current liabilities” on the Consolidated Statement of Financial Condition. The Company’s management believes the resolution of tax matters will not have a material effect on the Company’s consolidated financial condition. However, to the extent the Company is required to pay amounts in excess of its reserves, a resolution could have a material impact on its Consolidated Statement of Income for a particular future period. In addition, an unfavorable tax settlement could require use of cash and result in an increase in the effective tax rate in the period in which such resolution occurs.
Deferred Revenue	Deferred Revenue Deferred revenues represent amounts billed to customers for products and services in advance of delivery. The Company’s clients generally pay subscription fees annually or quarterly in advance. Deferred revenue is generally amortized ratably over the service period as revenue recognition criteria are met. Where the service period has not begun and the client has not paid or the contract has not been renewed, deferred revenues and accounts receivable are not recognized.
Goodwill	Goodwill Goodwill is recorded as part of the Company’s acquisitions of businesses when the purchase price exceeds the fair value of the net tangible and separately identifiable intangible assets acquired. The Company’s goodwill is not amortized, but rather is subject to an impairment test each year, or more often if conditions indicate impairment may have occurred, pursuant to ASC Subtopic 350-10, “ Intangibles—Goodwill and Other The Company tests goodwill for impairment on an annual basis on July 1 and on an interim basis when certain events and circumstances exist. The testing for impairment is performed at the reporting unit level. Goodwill impairment is determined by comparing the fair value of a reporting unit with its carrying value. If the estimated fair value exceeds the carrying value, goodwill at the reporting unit level is not deemed to be impaired. If the estimated fair value is below carrying value, however, further analysis is required to determine the amount of impairment, if any. If necessary an impairment charge will be recorded up to, but not more than, the total amount of goodwill allocated to the reporting unit. The Company completed its annual goodwill impairment test as of July 1, 2017 on its four reporting units, which are the same as its four operating segments. The Company performed a step zero, qualitative impairment test on each of its Index, Analytics and ESG operating segments and determined that it was more likely than not that the fair value for each of the Index, Analytics and ESG operating segments was not less than the carrying value for each. As revenues have been below management’s expectations for the Real Estate segment, the Company performed a step 1, quantitative impairment test for this segment and determined that the fair value substantially exceeded its carrying value. As the estimated fair value of the Company’s reporting units exceeded their carrying value on the testing dates, no impairment of goodwill was recorded during the years ended December 31, 2017, 2016 and 2015.
Intangible Assets	Intangible Assets The Company amortizes definite-lived intangible assets over their estimated useful lives. Definite-lived intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value of the asset may not be recoverable. The Company also reviews the useful lives on a quarterly basis to determine if the period of economic benefit has changed. If the carrying value of an intangible asset exceeds its fair value an impairment charge would be recognized in an amount equal to the amount by which the carrying value of the intangible asset exceeds its fair value. The Company has not identified a triggering event during any of the periods presented and as such has not recorded any impairment charges . The Company had no indefinite-lived intangibles.
Foreign Currency Translation	Foreign Currency Translation Assets and liabilities of operations having non-U.S. dollar functional currencies are translated at year-end exchange rates, and income statement accounts are translated at weighted average exchange rates for the year. Gains or losses resulting from translating foreign currency financial statements, net of related tax effects, are reflected in accumulated other comprehensive loss, a separate component of shareholders’ equity. Gains or losses resulting from foreign currency transactions incurred in currencies other than the local functional currency are included in non-operating “Other expense (income)” on the Consolidated Statement of Income.
Derivative Instruments	Derivative Instruments The Company applies ASC Subtopic 815-10, “ Derivatives and Hedging, For derivative instruments that are designated and qualify as hedging instruments for accounting purposes, the Company documents and links the relationships between the hedging instruments and hedged items. The Company also assesses and documents at the hedge’s inception whether the derivatives used in hedging transactions were effective in offsetting changes in fair values associated with the hedged items. ASC Subtopic 815-10 provides that, for derivative instruments that qualify for hedge accounting being used to hedge cash flows, changes in the fair value are recognized in accumulated other comprehensive income (loss), a separate component of shareholders’ equity, until the hedged item is recognized in earnings. In addition, the ineffective portion of a derivative’s change in fair value is immediately recognized in earnings. The Company manages foreign currency exchange rate risk through the use of derivative financial instruments comprised principally of forward contracts on foreign currency which are not designated as hedging instruments for accounting purposes. The objective of the derivative instruments is to minimize the income statement impact associated with assets and liabilities that are denominated in certain foreign currencies. Derivative instruments that do not qualify for hedge accounting are carried at fair value on the Consolidated Statement of Financial Condition with gains and losses recorded in the Consolidated Statement of Income in the period in which they are realized.
Property, Equipment and Leasehold Improvements	Property, Equipment and Leasehold Improvements Property, equipment and leasehold improvements are stated at cost less accumulated depreciation and amortization. Depreciation of furniture and fixtures and computer and communications equipment are amortized using the straight-line method over the estimated useful life of the asset.
Treasury Stock	Treasury Stock The Company holds repurchased shares of common stock as treasury stock. The Company accounts for treasury stock under the cost method and includes treasury stock as a component of shareholders’ equity. In accordance with ASC Subtopic 505-10, “ Equity
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts The Company primarily licenses its products and services to institutional investors mainly in the United States, Europe and Asia (primarily Hong Kong and Japan). The Company periodically reviews receivable balances and maintains an allowance on customer accounts where estimated losses may result from the inability of its customers to make required payments. The Company does not require collateral. An allowance for doubtful accounts is recorded when it is probable and estimable that a receivable will not be collected. Changes in the allowance for doubtful accounts from December 31, 2014 to December 31, 2017 were as follows: Amount (in Balance as of December 31, 2014 $ 857 Addition to provision 940 Amounts written off, net of recoveries (680 ) Balance as of December 31, 2015 $ 1,117 Addition to provision 1,011 Amounts written off, net of recoveries (1,093 ) Balance as of December 31, 2016 $ 1,035 Addition to provision 1,422 Amounts written off, net of recoveries (757 ) Balance as of December 31, 2017 $ 1,700
Accrued Compensation	Accrued Compensation The Company makes significant estimates in determining its accrued non-stock based compensation and benefits expenses. A significant portion of the Company’s employee incentive compensation programs are discretionary. At the end of each fiscal year, the Company determines the amount of discretionary cash bonus expense. These estimates reflect an assessment of performance versus targets and other key performance indicators at the Company, operating segment and employee level. The Company also reviews compensation and benefits expenses throughout the year to determine how overall performance compares to management’s expectations. These and other factors, including historical performance, are taken into account in accruing discretionary cash compensation estimates quarterly.
Concentrations	Concentrations For the years ended December 31, 2017 and 2015, BlackRock, Inc. accounted for 11.5% and 10.3%, respectively, of the Company’s consolidated operating revenues while no single customer represented 10.0% or more of the Company’s consolidated operating revenues for the year ended December 31, 2016. For the years ended December 31, 2017, 2016 and 2015, BlackRock, Inc. accounted for 20.0%, 17.3% and 19.2%, respectively, of the Index segment’s operating revenues. No single customer accounted for 10.0% or more of operating revenues within the Analytics and All Other segments for the years ended December 31, 2017, 2016 and 2015.
Recent Accounting Standards Updates	In May 2014, the FASB issued Accounting Standards Update 2014-09, “Revenue from Contracts with Customers (Topic 606),” “Deferral of the Effective Date,” In March 2016, the FASB issued Accounting Standards Update 2016-08, “ Principal Versus Agent Considerations (Reporting Revenue Gross Versus Net). Identifying Performance Obligations and Licensing. Narrow-Scope Improvements and Practical Expedients. Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers. In February 2016, the FASB issued Accounting Standards Update No. 2016-02, “ Leases (Topic 842), In March 2016, the FASB issued Accounting Standards Update No. 2016-09, “ Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting In June 2016, the FASB issued Accounting Standards Update No. 2016-13, “ Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, In January 2017, the FASB issued Accounting Standards Update No. 2017-01, “ Business Combinations (Topic 805): Clarifying the Definition of a Business, In January 2017, the FASB issued Accounting Standards Update No. 2017-04, “ Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, In February 2017, the FASB issued Accounting Standards Update No. 2017-07, “ Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost, In May 2017, the FASB issued Accounting Standards Update No. 2017-09, “ Compensation—Stock Compensation (Topic 718), Scope of Modification Accounting, In August 2017, the FASB issued Accounting Standards Update No. 2017-12, “ Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities, On December 22, 2017 the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (“Tax Reform”). Given the significance of the legislation, the SEC staff issued Staff Accounting Bulletin No. 118, “ Income Tax Accounting Implications of the Tax Cuts and Jobs Act,

Introduction and Basis of Pre24

Introduction and Basis of Presentation (Tables)	12 Months Ended
	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Changes in Allowance for Doubtful Accounts	Changes in the allowance for doubtful accounts from December 31, 2014 to December 31, 2017 were as follows: Amount (in Balance as of December 31, 2014 $ 857 Addition to provision 940 Amounts written off, net of recoveries (680 ) Balance as of December 31, 2015 $ 1,117 Addition to provision 1,011 Amounts written off, net of recoveries (1,093 ) Balance as of December 31, 2016 $ 1,035 Addition to provision 1,422 Amounts written off, net of recoveries (757 ) Balance as of December 31, 2017 $ 1,700

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Computation of Basic and Diluted EPS	The following table presents the computation of basic and diluted EPS: Years Ended December 31, December 31, December 31, 2017 2016 2015 (in thousands, except per share data) Income from continuing operations, net of income taxes $ 303,972 $ 260,855 $ 230,038 Loss from discontinued operations, net of income taxes — — (6,390 ) Net income $ 303,972 $ 260,855 $ 223,648 Basic weighted average common shares outstanding 90,336 95,986 109,124 Effect of dilutive securities: Stock options and restricted stock units 1,578 554 802 Diluted weighted average common shares outstanding 91,914 96,540 109,926 Earnings per basic common share from continuing operations $ 3.36 $ 2.72 $ 2.11 Loss per basic common share from discontinued operations — — (0.06 ) Earnings per basic common share $ 3.36 $ 2.72 $ 2.05 Earnings per diluted common share from continuing operations $ 3.31 $ 2.70 $ 2.09 Loss per diluted common share from discontinued operations — — (0.06 ) Earnings per diluted common share $ 3.31 $ 2.70 $ 2.03

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Summary of Future Minimum Commitments Under Operating Leases	Future minimum commitments for the Company’s operating leases in place as of December 31, 2017 are as follows: Years Ending December 31, Amount (in 2018 $ 30,210 2019 25,346 2020 21,943 2021 19,094 2022 16,208 Thereafter 117,853 Total $ 230,654
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 Consolidated Statements of Financial Condition: As of Consolidated Statements of December 31, December 31, (in thousands) Financial Condition Location 2017 2016 Non-designated hedging instruments: Asset derivatives: Foreign exchange contracts Prepaid and other assets $ - $ 27 Liability derivatives: Foreign exchange contracts Other accrued liabilities $ (118 ) $ (124 )
Effect of Financial Derivatives on Statements of Income	The following tables present the effect of the Company’s financial derivatives and the location in which they are presented on the Company’s Consolidated Statements of Financial Condition and Consolidated Statements of Income: Amount of Gain or (Loss) Recognized in Income on Derivatives for the Derivatives Not Designated as Location of Gain or Years Ended Hedging Instruments (Loss) Recognized December 31, December 31, December 31, (in thousands) in Income on Derivatives 2017 2016 2015 Foreign exchange contracts Other expense (income) $ (1,847 ) $ 1,566 $ 366

Property, Equipment and Lease27

Property, Equipment and Leasehold Improvements (Tables)	12 Months Ended
	Dec. 31, 2017
Property Plant And Equipment [Abstract]
Schedule of Property, Equipment and Leasehold Improvements	Property, equipment and leasehold improvements at December 31, 2017 and 2016 consisted of the following: As of Estimated December 31, December 31, Useful 2017 2016 (in thousands) Computer & related equipment 2 $ 200,592 $ 162,306 Furniture & fixtures 7 years 10,591 9,724 Leasehold improvements 1 to 21 years 51,128 49,442 Work-in-process — 3,406 10,954 Subtotal 265,717 232,426 Accumulated depreciation and amortization (171,280 ) (136,841 ) Property, equipment and leasehold improvements, net $ 94,437 $ 95,585

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Change to Company's Goodwill	The change to the Company’s goodwill was as follows: (in thousands) Index Analytics All Other Total Goodwill at December 31, 2015 $ 1,208,454 $ 302,551 $ 54,616 $ 1,565,621 Changes to goodwill — 60 (1) (110 ) (2) (50 ) Foreign exchange translation adjustment (6,006 ) — (3,715 ) (9,721 ) Goodwill at December 31, 2016 $ 1,202,448 $ 302,611 $ 50,791 $ 1,555,850 Foreign exchange translation adjustment 2,952 — 1,819 4,771 Goodwill at December 31, 2017 $ 1,205,400 $ 302,611 $ 52,610 $ 1,560,621 (1) Reflects the final working capital adjustment payment made during the year ended December 31, 2016 to complete the acquisition of the Insignis business (“Insignis”). (2) Reflects the value disposed in the sale of the Real Estate occupiers business.
Schedule of Gross Carrying and Accumulated Amortization Amounts Related to Company's Identifiable Intangible Assets	The gross carrying and accumulated amortization amounts related to the Company’s identifiable intangible assets were as follows: As of Estimated December 31, December 31, Useful Lives 2017 2016 (in thousands) Gross intangible assets: Customer relationships 5 to 21 years $ 361,199 $ 361,199 Trademarks/trade names 5 to 21.5 years 223,382 223,382 Technology/software 3 to 8.5 years 225,407 210,013 Proprietary data 13 years 28,627 28,627 Covenant not to compete 2 years - 1,225 Subtotal 838,615 824,446 Foreign exchange translation adjustment (9,167 ) (13,946 ) Total gross intangible assets $ 829,448 $ 810,500 Accumulated amortization: Customer relationships $ (189,100 ) $ (166,923 ) Trademarks/trade names (116,691 ) (105,077 ) Technology/software (193,095 ) (184,290 ) Proprietary data (10,352 ) (8,571 ) Covenant not to compete - (1,089 ) Subtotal (509,238 ) (465,950 ) Foreign exchange translation adjustment 1,626 3,090 Total accumulated amortization $ (507,612 ) $ (462,860 ) Net intangible assets: Customer relationships $ 172,099 $ 194,276 Trademarks/trade names 106,691 118,305 Technology/software 32,312 25,723 Proprietary data 18,275 20,056 Covenant not to compete - 136 Subtotal 329,377 358,496 Foreign exchange translation adjustment (7,541 ) (10,856 ) Total net intangible assets $ 321,836 $ 347,640
Estimated Amortization Expense for Succeeding Years	Estimated amortization expense for succeeding years is presented below: Years Ending December 31, Amortization Expense (in thousands) 2018 $ 45,526 2019 43,593 2020 41,583 2021 38,488 2022 35,730 Thereafter 116,916 Total $ 321,836

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Schedule of Company's Common Stock Repurchases Pursuant to Open Market Repurchases	The following table provides information with respect to repurchases of the Company’s common stock pursuant to open market repurchases: Year Ended Average Price Paid Per Share Total Number of Shares Repurchased Dollar Value of Shares Repurchased (in thousands, except per share data) December 31, 2015 $ 62.63 10,710 $ 670,824 December 31, 2016 $ 73.71 10,303 $ 759,427 December 31, 2017 $ 87.96 1,556 $ 136,899
Schedule of Cash Dividends Declared and Distributed Per Common Share	The following table presents cash dividends declared and distributed per common share for the periods indicated: Dividends Per Share Declared Distributed Deferred 2017 (in thousands, except per share data) Three Months Ended March 31, $ 0.28 $ 25,769 $ 25,500 $ 269 Three Months Ended June 30, 0.28 25,710 25,444 266 Three Months Ended September 30, 0.38 34,768 34,403 365 Three Months Ended December 31, 0.38 34,745 34,448 297 Total $ 1.32 $ 120,992 $ 119,795 $ 1,197 2016 Three Months Ended March 31, $ 0.22 $ 22,046 $ 21,889 $ 157 Three Months Ended June 30, 0.22 21,588 21,391 197 Three Months Ended September 30, 0.28 26,936 26,680 256 Three Months Ended December 31, 0.28 26,524 26,304 220 Total $ 1.00 $ 97,094 $ 96,264 $ 830 2015 Three Months Ended March 31, $ 0.18 $ 20,424 $ 20,411 $ 13 Three Months Ended June 30, 0.18 20,444 20,442 2 Three Months Ended September 30, 0.22 24,210 24,152 58 Three Months Ended December 31, 0.22 22,803 22,792 11 Total $ 0.80 $ 87,881 $ 87,797 $ 84
Summary of Activity Related to Shares of Common Stock Issued and Repurchased	The following table presents activity related to shares of common stock issued and repurchased for the periods indicated: Common Treasury Common Stock Issued Stock Outstanding Balance At December 31, 2014 126,637,390 (14,564,921 ) 112,072,469 Dividend payable/paid 802 (385 ) 417 Common stock issued and exercise of stock options 1,558,965 — 1,558,965 Shares withheld for tax withholding and exercises — (763,558 ) (763,558 ) Shares repurchased under stock repurchase programs — (11,856,169 ) (11,856,169 ) Shares issued to directors 3,032 (2,008 ) 1,024 Balance At December 31, 2015 128,200,189 (27,187,041 ) 101,013,148 Dividend payable/paid 892 (472 ) 420 Common stock issued and exercise of stock options 788,304 — 788,304 Shares withheld for tax withholding and exercises — (219,921 ) (219,921 ) Shares repurchased under stock repurchase programs — (10,303,047 ) (10,303,047 ) Shares issued to directors 6,959 (6,273 ) 686 Balance At December 31, 2016 128,996,344 (37,716,754 ) 91,279,590 Dividend payable/paid 156 — 156 Common stock issued and exercise of stock options 538,499 — 538,499 Shares withheld for tax withholding and exercises — (158,090 ) (158,090 ) Shares repurchased under stock repurchase programs — (1,556,313 ) (1,556,313 ) Shares issued to directors 8,857 (7,814 ) 1,043 Balance At December 31, 2017 129,543,856 (39,438,971 ) 90,104,885
Components of Share-Based Compensation Expense	The components of share-based compensation expense related to the awards to Company employees and directors who are not employees of the Company of restricted stock units and restricted stock awards (representing shares of common stock) and options to purchase shares of common stock, as applicable, are presented below: Years Ended December 31, December December 31, (in thousands) 2017 2016 2015 Deferred stock $ 37,921 $ 32,525 $ 27,549 Stock options — — (73 ) Total $ 37,921 $ 32,525 $ 27,476
Summary of Share-based Compensation Expense	The following table presents the amount of share-based compensation expense by category for the periods indicated: Years Ended December 31, December 31, December 31, (in thousands) 2017 2016 2015 Cost of revenues $ 9,707 $ 7,971 $ 6,909 Selling and marketing 11,355 9,526 6,564 Research and development 3,477 2,970 2,823 General and administrative 13,382 12,058 11,180 Total share-based compensation expense $ 37,921 $ 32,525 $ 27,476
Summary of Vested and Unvested Deferred Stock Awards Activity	The following table presents activity concerning the Company’s vested and unvested deferred stock awards applicable to its employees (share data in thousands) for the period indicated: Weighted Average Grant Number of Date Fair For the Year Ended December 31, 2017 Shares Value Vested and unvested deferred stock awards at December 31, 2016 1,507 $ 61.82 Granted 302 $ 88.01 Conversion to common stock (351 ) $ 56.83 Canceled (39 ) $ 66.25 Vested and unvested deferred stock awards at December 31, 2017 (1) 1,419 $ 68.50 (1) As of December 31, 2017, 1,366 restricted stock units and restricted stock awards, with a weighted average price of $68.35, were vested or expected to vest.
Summary of Unvested Deferred Stock Awards Activity	The following table presents activity concerning the Company’s unvested deferred stock awards related to its employees (share data in thousands): Weighted Average Grant Number of Date Fair For the Year Ended December 31, 2017 Shares Value Unvested deferred stock awards at December 31, 2016 1,207 $ 62.89 Granted 277 $ 88.27 Vested (279 ) $ 58.06 Canceled (39 ) $ 66.25 Unvested deferred stock awards at December 31, 2017 1,166 $ 69.96 Unvested deferred stock awards expected to vest 1,113 $ 69.84
Summary of Stock Options Activity	The following table presents activity concerning MSCI stock options granted to the Company’s employees for the year ended December 31, 2017 (option data and dollar values in thousands, except exercise price): Weighted Weighted Average Number Average Remaining Aggregated of Exercise Life Intrinsic For the Year Ended December 31, 2017 Options Price (Years) Value Options outstanding at December 31, 2016 269 $ 24.06 2.22 N/A Granted or assumed — $ — N/A N/A Forfeited — $ — N/A N/A Conversion to common stock (124 ) $ 21.24 N/A N/A Options outstanding and exercisable at December 31, 2017 145 $ 26.47 2.11 $ 14,519
Summary of Stock Options Outstanding and Exercisable by Exercise Price Range	The following table presents information relating to the Company’s outstanding and exercisable stock options as of December 31, 2017 (number of options outstanding and aggregate intrinsic value data in thousands): As of December 31, 2017 Options Outstanding Weighted Average Average Aggregate Number Exercise Remaining Intrinsic Range of Exercise Prices Outstanding Price Life (Years) Value $15.18 to $16.48 38 $ 16.47 1.15 $ 4,175 $20.45 to $24.11 16 $ 20.62 1.77 $ 1,733 $ 25.64 41 $ 25.64 2.11 $ 4,139 $ 36.70 50 $ 36.70 2.95 $ 4,472 Total 145 $ 14,519

Reclassifications out of Accu30

Reclassifications out of Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Schedule of Reclassifications out of Accumulated Other Comprehensive Income (Loss)	Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (1) Details about Accumulated Other Amount Reclassified from Accumulated Affected Comprehensive Income (Loss) Components Other Comprehensive Income (Loss) Consolidated Statements of Income Years Ended December 31, December 31, December 31, 2017 2016 2015 (in Defined benefit pension plans Amount recognized as a component of net periodic benefit expense for curtailments and settlements $ (281 ) $ (261 ) $ (563 ) 77 73 153 Provision for income taxes Total reclassifications for the period, net of tax $ (204 ) $ (188 ) $ (410 ) (1) Amounts in parentheses indicate expenses or losses moved to the Consolidated Statements of Income.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Summary of Provision for Income Taxes (Benefits) by Taxing Jurisdiction	The provision for income taxes (benefits) by taxing jurisdiction consisted of: Years Ended December 31, December 31, December 31, 2017 2016 2015 (in thousands) Current U.S. federal $ 133,250 $ 93,071 $ 85,540 U.S. state and local 16,312 16,363 22,108 Non U.S. 32,267 32,616 22,156 181,829 142,050 129,804 Deferred U.S. federal (12,502 ) (13,010 ) (10,546 ) U.S. state and local (2,119 ) (2,235 ) 1,460 Non U.S. (4,281 ) (1,722 ) (1,202 ) (18,902 ) (16,967 ) (10,288 ) Provision for income taxes from continuing operations $ 162,927 $ 125,083 $ 119,516 Provision for income taxes from discontinued operations $ — $ — $ 6,390
Reconciliation of Provision to U.S. Federal Statutory Income Tax Rate for Income from Continuing Operations	The following table reconciles the provision to the U.S. federal statutory income tax rate for income from continuing operations: Years Ended December 31, December 31, December 31, 2017 2016 2015 U.S. federal statutory income tax rate 35.00 % 35.00 % 35.00 % U.S. state and local income taxes, net of U.S. federal income tax benefits 1.84 % 2.38 % 4.44 % Change in tax rates applicable to non-U.S. earnings (7.60 %) (3.73 %) (2.73 %) Domestic tax credits and incentives (0.24 %) (0.26 %) (2.62 %) Net tax charge related to Tax Reform 7.40 % — % — % Excess Stock Based Compensation (1.25 %) — % — % Other (0.25 %) (0.98 %) 0.10 % Effective income tax rate 34.90 % 32.41 % 34.19 %
Significant Components of Deferred Tax Assets and Liabilities	Significant components of the Company’s deferred tax assets and liabilities as of December 31, 2017 and 2016, were as follows: As of December 31, December 31, 2017 2016 (in thousands) Deferred tax assets: Employee compensation and benefit plans $ 19,646 $ 27,914 Deferred rent 5,308 7,869 Pension 1,520 1,965 Unearned revenue 853 1,322 Loss carryforwards - non-current 18,105 27,616 Other 1,435 558 Subtotal 46,867 67,244 Less: valuation allowance (11,575 ) (17,807 ) Total deferred tax assets $ 35,292 $ 49,437 Deferred tax liabilities: Intangible assets $ (73,634 ) $ (121,900 ) Investment in foreign subsidiaries (16,108 ) — Property, equipment and leasehold improvements, net (11,564 ) (12,073 ) Total deferred tax liabilities $ (101,306 ) $ (133,973 ) Net deferred tax liabilities $ (66,014 ) $ (84,536 )
Summary of Deferred Tax Asset Valuation Allowance	The following table presents changes in the Company’s deferred tax asset valuation allowance for the periods indicated: Years Ended December 31, December 31, December 31, 2017 2016 2015 (in thousands) Beginning balance $ 17,807 $ 21,052 $ 21,232 Additions charged to cost and expenses 324 1,862 — Additions charged to other accounts — — — Deductions (6,556 ) (5,107 ) (180 ) Ending balance $ 11,575 $ 17,807 $ 21,052
Summary of Components of Income Before Provision for Income Taxes	The following table presents the components of income before provision for income taxes generated by domestic or foreign operations for the periods indicated: Years Ended December 31, December 31, December 31, 2017 2016 2015 (in thousands) Domestic $ 283,779 $ 263,536 $ 282,764 Foreign (1) 183,120 122,402 66,790 Total income before provision for income taxes $ 466,899 $ 385,938 $ 349,554
Reconciliation of Unrecognized Tax Benefits	The following table presents a reconciliation of the beginning and ending amount of the gross unrecognized tax benefits, excluding interest and penalties, for the years ended December 31, 2017, 2016 and 2015: Years Ended December 31, December 31, December 31, Gross unrecognized tax benefits 2017 2016 2015 (in thousands) Beginning balance $ 7,936 $ 8,692 $ 6,525 Increases based on tax positions related to the current period 3,389 575 536 Increases based on tax positions related to prior periods 519 135 2,131 Decreases based on tax positions related to prior periods (6 ) (3 ) (500 ) Decreases related to settlements with taxing authorities (1,152 ) (1,463 ) — Decreases related to a lapse of applicable statute of limitations (664 ) — — Ending balance $ 10,022 $ 7,936 $ 8,692

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Operating Revenue by Reportable Segment	The following table presents operating revenue by reportable segment for the periods indicated: Years Ended December 31, December 31, December 31, 2017 2016 2015 (in thousands) Operating revenues Index $ 718,959 $ 613,551 $ 558,964 Analytics 458,269 448,353 433,424 All Other 96,944 88,765 82,625 Total $ 1,274,172 $ 1,150,669 $ 1,075,013
Segment Profitability and Reconciliation to Net Income	The following table presents segment profitability and a reconciliation to net income for the periods indicated: Years Ended December 31, December 31, December 31, 2017 2016 2015 (in thousands) Index Adjusted EBITDA $ 522,043 $ 431,478 $ 392,987 Analytics Adjusted EBITDA 125,349 128,507 95,468 All Other Adjusted EBITDA 11,783 9,472 (6,758 ) Total operating segment profitability 659,175 569,457 481,697 Amortization of intangible assets 44,547 47,033 46,910 Depreciation and amortization of property, equipment and leasehold improvements 35,440 34,320 30,889 Operating income 579,188 488,104 403,898 Other expense (income), net 112,289 102,166 54,344 Provision for income taxes 162,927 125,083 119,516 Income from continuing operations 303,972 260,855 230,038 Income (loss) from discontinued operations, net of income taxes — — (6,390 ) Net income $ 303,972 $ 260,855 $ 223,648
Revenue by Geographic Area	Revenue by geography is based on the shipping address of the ultimate customer utilizing the product. The following table presents revenue by geographic area for the periods indicated: Years Ended December 31, December 31, December 31, (in thousands) 2017 2016 2015 Revenues Americas: United States $ 622,132 $ 556,777 $ 519,429 Other 48,139 45,185 41,552 Total Americas 670,271 601,962 560,981 Europe, the Middle East and Africa ("EMEA"): United Kingdom 193,831 175,749 166,019 Other 250,267 229,010 215,192 Total EMEA 444,098 404,759 381,211 Asia & Australia: Japan 54,351 52,161 45,371 Other 105,452 91,787 87,450 Total Asia & Australia 159,803 143,948 132,821 Total $ 1,274,172 $ 1,150,669 $ 1,075,013
Long-Lived Assets by Geographic Area	Long-lived assets consist of property, equipment, leasehold improvements, goodwill and intangible assets, net of accumulated depreciation and amortization. The following table presents long-lived assets by geographic area on the dates indicated: As of December 31, December 31, 2017 2016 (in thousands) Long-lived assets Americas: United States $ 1,847,605 $ 1,876,366 Other 1,685 1,543 Total Americas 1,849,290 1,877,909 EMEA: United Kingdom 94,782 89,466 Other 22,394 23,780 Total EMEA 117,176 113,246 Asia & Australia: Japan 432 357 Other 9,996 7,563 Total Asia & Australia 10,428 7,920 Total $ 1,976,894 $ 1,999,075

Quarterly Results of Operatio33

Quarterly Results of Operations (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Summary of Quarterly Results of Operations	2017 2016 First Second Third Fourth First Second Third Fourth Quarter Quarter Quarter Quarter Quarter Quarter Quarter Quarter (in thousands, except per share data) Operating revenues $ 301,207 $ 316,089 $ 322,097 $ 334,779 $ 278,828 $ 290,596 $ 288,433 $ 292,812 Cost of revenues 67,521 68,595 68,491 69,306 63,172 62,130 62,986 63,819 Selling and marketing 43,014 41,594 44,918 47,771 41,689 41,854 41,514 41,609 Research and development 18,977 18,203 17,983 20,721 18,928 18,566 18,750 18,960 General and administrative 21,004 21,448 22,103 23,348 21,890 22,019 21,859 21,467 Amortization of intangible assets 11,251 11,122 10,614 11,560 11,840 11,943 11,752 11,498 Depreciation and amortization of property, equipment and leasehold improvements 8,838 9,159 9,325 8,118 8,168 8,393 8,312 9,447 Total operating expenses 170,605 170,121 173,434 180,824 165,687 164,905 165,173 166,800 Operating income 130,602 145,968 148,663 153,955 113,141 125,691 123,260 126,012 Interest income (932 ) (1,310 ) (1,835 ) (2,237 ) (621 ) (585 ) (799 ) (901 ) Interest expense 29,024 29,027 29,020 29,027 22,904 22,918 26,790 29,039 Other expense (income) 885 740 675 205 81 2,814 (253 ) 779 Other expense (income), net 28,977 28,457 27,860 26,995 22,364 25,147 25,738 28,917 Income from continuing operations before provision for income taxes 101,625 117,511 120,803 126,960 90,777 100,544 97,522 97,095 Provision for income taxes 28,674 36,245 35,650 62,358 30,410 33,587 32,241 28,845 Net income $ 72,951 $ 81,266 $ 85,153 $ 64,602 $ 60,367 $ 66,957 $ 65,281 $ 68,250 Earnings per basic common share $ 0.80 $ 0.90 $ 0.94 $ 0.72 $ 0.61 $ 0.69 $ 0.69 $ 0.73 Earnings per diluted common share $ 0.80 $ 0.89 $ 0.93 $ 0.70 $ 0.60 $ 0.69 $ 0.68 $ 0.73 Weighted average shares outstanding used in computing per share data Basic 90,708 90,404 90,112 90,130 99,425 96,412 94,823 93,327 Diluted 91,624 91,708 91,868 92,467 99,998 96,888 95,473 93,845

Introduction and Basis of Pre34

Introduction and Basis of Presentation - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017USD ($)Customer	Dec. 31, 2016USD ($)Customer	Dec. 31, 2015USD ($)Customer
Introduction And Basis Of Presentation [Line Items]
Minimum percentage of voting stock for consolidation	50.00%
Maximum percentage of voting stock in variable interest entity for consolidation	20.00%
Cost method investments | $	$ 0
Capitalized software development costs | $	15,640,000	$ 10,344,000	$ 8,500,000
Impairment of goodwill | $	$ 0	$ 0	$ 0
Operating Revenues [Member] | Customer Concentration Risk [Member]
Introduction And Basis Of Presentation [Line Items]
Percentage of operating revenues accounted for by major customer	10.00%
Number of major customers accounted for 10.0% or more of revenues | Customer	0
Operating Revenues [Member] | Customer Concentration Risk [Member] | Blackrock Inc [Member]
Introduction And Basis Of Presentation [Line Items]
Percentage of operating revenues accounted for by major customer	11.50%		10.30%
Minimum [Member] | Software and Software Development Costs [Member]
Introduction And Basis Of Presentation [Line Items]
Estimates of useful lives	3 years
Maximum [Member] | Software and Software Development Costs [Member]
Introduction And Basis Of Presentation [Line Items]
Estimates of useful lives	5 years
Analytics [Member] | Operating Revenues [Member] | Customer Concentration Risk [Member]
Introduction And Basis Of Presentation [Line Items]
Number of major customers accounted for 10.0% or more of revenues | Customer	0	0	0
Index [Member] | Operating Revenues [Member] | Customer Concentration Risk [Member] | Blackrock Inc [Member]
Introduction And Basis Of Presentation [Line Items]
Percentage of operating revenues accounted for by major customer	20.00%	17.30%	19.20%
All Other [Member] | Operating Revenues [Member] | Customer Concentration Risk [Member]
Introduction And Basis Of Presentation [Line Items]
Number of major customers accounted for 10.0% or more of revenues | Customer	0	0	0

Introduction and Basis of Pre35

Introduction and Basis of Presentation - Changes in Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Balance at beginning of year	$ 1,035	$ 1,117	$ 857
Addition to provision	1,422	1,011	940
Amounts written off, net of recoveries	(757)	(1,093)	(680)
Balance at ending of year	$ 1,700	$ 1,035	$ 1,117

Recent Accounting Standards U36

Recent Accounting Standards Updates - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in net cash provided by operating activities	$ 404,158	$ 442,363	$ 321,247
Decrease in net cash used in financing activities	(267,543)	(372,899)	4,696
Accounting Standards Update 2016-09 [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Amount of excess tax benefits recognition	$ 5,700
Effect of change on diluted earnings per share	$ 0.06
Increase in net cash provided by operating activities		7,600	15,300
Decrease in net cash used in financing activities		$ (7,600)	$ (15,300)

Earnings Per Common Share - Add

Earnings Per Common Share - Additional Information (Detail) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Anti-dilutive securities excluded from the calculation of diluted EPS	987	398	3,778

Earnings Per Common Share - Com

Earnings Per Common Share - Computation of Basic and Diluted EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Income from continuing operations, net of income taxes									$ 303,972	$ 260,855	$ 230,038
Loss from discontinued operations, net of income taxes											(6,390)
Net income	$ 64,602	$ 85,153	$ 81,266	$ 72,951	$ 68,250	$ 65,281	$ 66,957	$ 60,367	$ 303,972	$ 260,855	$ 223,648
Basic weighted average common shares outstanding	90,130	90,112	90,404	90,708	93,327	94,823	96,412	99,425	90,336	95,986	109,124
Effect of dilutive securities:
Stock options and restricted stock units									1,578	554	802
Diluted weighted average common shares outstanding	92,467	91,868	91,708	91,624	93,845	95,473	96,888	99,998	91,914	96,540	109,926
Earnings per basic common share from continuing operations									$ 3.36	$ 2.72	$ 2.11
Loss per basic common share from discontinued operations											(0.06)
Earnings per basic common share	$ 0.72	$ 0.94	$ 0.90	$ 0.80	$ 0.73	$ 0.69	$ 0.69	$ 0.61	3.36	2.72	2.05
Earnings per diluted common share from continuing operations									3.31	2.70	2.09
Loss per diluted common share from discontinued operations											(0.06)
Earnings per diluted common share	$ 0.70	$ 0.93	$ 0.89	$ 0.80	$ 0.73	$ 0.68	$ 0.69	$ 0.60	$ 3.31	$ 2.70	$ 2.03

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	Aug. 04, 2016	Aug. 13, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Nov. 20, 2014
Schedule Of Commitments And Contingencies [Line Items]
Annual rent expense			$ 24,200,000	$ 24,200,000	$ 26,500,000
Revolving credit agreement, conditional description			The 2014 Revolving Credit Agreement had an initial term of five years with an option to extend for two additional one-year terms. On August 4, 2016, the Company entered into Amendment No. 1 (the “Amendment”) to the 2014 Revolving Credit Agreement (the 2014 Revolving Credit Agreement as so amended, the “Revolving Credit Agreement”). The Amendment, among other things, (i) increased aggregate commitments available to be borrowed to $220.0 million, (ii) increased the maximum consolidated leverage ratio and (iii) extended the initial term to August 2021 with an option to extended for an additional one-year term. At December 31, 2017, the Revolving Credit Agreement was undrawn.
Long-term debt			$ 2,078,093,000	2,075,201,000
Deferred financing fees			21,900,000	24,800,000
Fair market value of debt obligations			2,231,100,000	$ 2,192,500,000
Other Expense (Income) [Member]
Schedule Of Commitments And Contingencies [Line Items]
Gain on sale of investment			800,000		$ 6,300,000
Derivatives not Designated as Hedging Instruments [Member] | Foreign Currency Forwards [Member]
Schedule Of Commitments And Contingencies [Line Items]
Foreign currency forwards, notional amount			10,500,000
Prepaid and Other Assets [Member]
Schedule Of Commitments And Contingencies [Line Items]
Deferred financing fees			500,000
Other Non-Current Assets [Member]
Schedule Of Commitments And Contingencies [Line Items]
Deferred financing fees			1,300,000
Long-term Debt [Member]
Schedule Of Commitments And Contingencies [Line Items]
Deferred financing fees			$ 21,900,000
2014 Revolving Credit Agreement [Member]
Schedule Of Commitments And Contingencies [Line Items]
Revolving credit facility, maximum borrowing						$ 200,000,000
Revolving credit agreement, term			5 years
Revolving Credit Agreement [Member]
Schedule Of Commitments And Contingencies [Line Items]
Revolving credit facility, maximum borrowing	$ 220,000,000
Revolving credit agreement, extended term	1 year
5.250% Senior Unsecured Notes Due 2024 [Member]
Schedule Of Commitments And Contingencies [Line Items]
Debt instrument principal amount						$ 800,000,000
Debt instrument interest rate						5.25%
Maturity date			Nov. 15, 2024
Redemption description			At any time prior to November 15, 2019, the Company may redeem all or part of the 2024 Senior Notes upon not less than 30 nor more than 60 days’ prior notice at a redemption price equal to the sum of (i) 100% of the principal amount thereof, plus (ii) a make-whole premium as of the date of redemption, plus (iii) accrued and unpaid interest and additional interest, if any, thereon, to the date of redemption.
Debt instrument description			Interest payments attributable to the 2024 Senior Notes are due on May 15 and November 15 of each year.
Debt instrument, first interest payment date			May 15, 2015
Term Loan [Member]
Schedule Of Commitments And Contingencies [Line Items]
Outstanding indebtedness, amount						$ 794,800,000
5.75% Senior Unsecured Notes Due 2025 [Member]
Schedule Of Commitments And Contingencies [Line Items]
Debt instrument principal amount		$ 800,000,000
Debt instrument interest rate		5.75%
Net proceeds from borrowing		$ 789,500,000
4.75% Senior Unsecured Notes Due 2026 [Member]
Schedule Of Commitments And Contingencies [Line Items]
Debt instrument principal amount	$ 500,000,000
Debt instrument interest rate	4.75%
Net proceeds from borrowing	$ 493,300,000
Maturity date			Aug. 1, 2016
Redemption description			At any time prior to August 1, 2021, the Company may redeem all or part of the 2026 Senior Notes upon not less than 30 nor more than 60 days’ prior notice at a redemption price equal to the sum of (i) 100% of the principal amount thereof, plus (ii) a make-whole premium as of the date of redemption, plus (iii) accrued and unpaid interest and additional interest, if any, thereon, to the date of redemption.
Percentage of aggregate principal amount redeemed			35.00%
Redemption price			104.75%
Debt instrument description			Interest payments attributable to the 2026 Senior Notes are due on February 1 and August 1 of each year.
Debt instrument, first interest payment date			Feb. 1, 2017
5.75% Senior Notes Due In 2025 [Member]
Schedule Of Commitments And Contingencies [Line Items]
Maturity date			Aug. 15, 2025
Redemption description			At any time prior to August 15, 2020, the Company may redeem all or part of the 2025 Senior Notes upon not less than 30 nor more than 60 days’ prior notice at a redemption price equal to the sum of (i) 100% of the principal amount thereof, plus (ii) a make-whole premium as of the date of redemption, plus (iii) accrued and unpaid interest and additional interest, if any, thereon, to the date of redemption.
Percentage of aggregate principal amount redeemed			35.00%
Redemption price			105.75%
Debt instrument description			Interest payments attributable to the 2025 Senior Notes are due on February 15 and August 15 of each year.
Debt instrument, first interest payment date			Feb. 16, 2016
Senior Notes [Member]
Schedule Of Commitments And Contingencies [Line Items]
Debt instrument principal amount			$ 2,100,000,000
Senior Notes and Revolving Credit Facility [Member]
Schedule Of Commitments And Contingencies [Line Items]
Deferred financing fees			$ 23,700,000

Commitments and Contingencies40

Commitments and Contingencies - Summary of Future Minimum Commitments Under Operating Leases (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Commitments And Contingencies Disclosure [Abstract]
2,018	$ 30,210
2,019	25,346
2,020	21,943
2,021	19,094
2,022	16,208
Thereafter	117,853
Total	$ 230,654

Commitments and Contingencies41

Commitments and Contingencies - Summary of Fair Values of Derivative Instruments (Detail) - Derivatives not Designated as Hedging Instruments [Member] - Foreign Exchange Contracts [Member] - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Prepaid and Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives		$ 27
Other Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability derivatives	$ (118)	$ (124)

Commitments and Contingencies42

Commitments and Contingencies - Effect of Financial Derivatives on Statements of Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Foreign Exchange Contracts [Member] | Derivatives not Designated as Hedging Instruments [Member] | Other Expense (Income) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivatives	$ (1,847)	$ 1,566	$ 366

Property, Equipment and Lease43

Property, Equipment and Leasehold Improvements - Schedule of Property, Equipment and Leasehold Improvements (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Computer & related equipment	$ 200,592	$ 162,306
Furniture & fixtures	10,591	9,724
Leasehold improvements	51,128	49,442
Work-in-process	3,406	10,954
Subtotal	265,717	232,426
Accumulated depreciation and amortization	(171,280)	(136,841)
Property, equipment and leasehold improvements, net	$ 94,437	$ 95,585
Computer & Related Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	2 years
Computer & Related Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	5 years
Furniture & Fixtures [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	7 years
Leasehold improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	1 year
Leasehold improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	21 years

Property, Equipment and Lease44

Property, Equipment and Leasehold Improvements - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Abstract]
Depreciation and amortization of property, equipment and leasehold improvements	$ 8,118	$ 9,325	$ 9,159	$ 8,838	$ 9,447	$ 8,312	$ 8,393	$ 8,168	$ 35,440	$ 34,320	$ 30,889

Goodwill and Intangible Asset45

Goodwill and Intangible Assets - Schedule of Change to Company's Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill, Beginning balance	$ 1,555,850	$ 1,565,621
Changes to goodwill		(50)
Foreign exchange translation adjustment	4,771	(9,721)
Goodwill, Ending balance	1,560,621	1,555,850
Index [Member]
Goodwill [Line Items]
Goodwill, Beginning balance	1,202,448	1,208,454
Foreign exchange translation adjustment	2,952	(6,006)
Goodwill, Ending balance	1,205,400	1,202,448
Analytics [Member]
Goodwill [Line Items]
Goodwill, Beginning balance	302,611	302,551
Changes to goodwill		60
Goodwill, Ending balance	302,611	302,611
All Other [Member]
Goodwill [Line Items]
Goodwill, Beginning balance	50,791	54,616
Changes to goodwill		(110)
Foreign exchange translation adjustment	1,819	(3,715)
Goodwill, Ending balance	$ 52,610	$ 50,791

Goodwill and Intangible Asset46

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Impairment of goodwill									$ 0	$ 0	$ 0
Amortization of intangible assets	$ 11,560,000	$ 10,614,000	$ 11,122,000	$ 11,251,000	$ 11,498,000	$ 11,752,000	$ 11,943,000	$ 11,840,000	$ 44,547,000	$ 47,033,000	$ 46,910,000

Goodwill and Intangible Asset47

Goodwill and Intangible Assets - Schedule of Gross Carrying and Accumulated Amortization Amounts Related to Company's Identifiable Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying value	$ 829,448	$ 810,500
Accumulated amortization	(507,612)	(462,860)
Net carrying value	321,836	347,640
Customer Relationships [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying value	361,199	361,199
Accumulated amortization	(189,100)	(166,923)
Net carrying value	$ 172,099	194,276
Customer Relationships [Member] | Minimum [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Estimated Remaining Useful Lives	5 years
Customer Relationships [Member] | Maximum [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Estimated Remaining Useful Lives	21 years
Trademarks/Trade Names [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying value	$ 223,382	223,382
Accumulated amortization	(116,691)	(105,077)
Net carrying value	$ 106,691	118,305
Trademarks/Trade Names [Member] | Minimum [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Estimated Remaining Useful Lives	5 years
Trademarks/Trade Names [Member] | Maximum [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Estimated Remaining Useful Lives	21 years 6 months
Technology/Software [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying value	$ 225,407	210,013
Accumulated amortization	(193,095)	(184,290)
Net carrying value	$ 32,312	25,723
Technology/Software [Member] | Minimum [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Estimated Remaining Useful Lives	3 years
Technology/Software [Member] | Maximum [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Estimated Remaining Useful Lives	8 years 6 months
Proprietary Data [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Estimated Remaining Useful Lives	13 years
Gross carrying value	$ 28,627	28,627
Accumulated amortization	(10,352)	(8,571)
Net carrying value	$ 18,275	20,056
Covenant Not to Compete [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Estimated Remaining Useful Lives	2 years
Gross carrying value		1,225
Accumulated amortization		(1,089)
Net carrying value		136
Subtotal [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying value	$ 838,615	824,446
Accumulated amortization	(509,238)	(465,950)
Net carrying value	329,377	358,496
Foreign Exchange Translation Adjustment [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying value	(9,167)	(13,946)
Accumulated amortization	1,626	3,090
Net carrying value	$ (7,541)	$ (10,856)

Goodwill and Intangible Asset48

Goodwill and Intangible Assets - Estimated Amortization Expense for Succeeding Years (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
2,018	$ 45,526
2,019	43,593
2,020	41,583
2,021	38,488
2,022	35,730
Thereafter	116,916
Net carrying value	$ 321,836	$ 347,640

Employee Benefits - Additional

Employee Benefits - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Benefit Plans [Line Items]
Pension and post-retirement benefit expenses	$ 22.5	$ 21.6	$ 23.1
Defined contribution plan expenses	19.2	17.6	18.4
Net periodic benefit expense	3.3	4	4.7
Fair value of the defined benefit plan assets	20.6	17.5
Other Non-current Liabilities [Member]
Employee Benefit Plans [Line Items]
Defined benefit plan, liability	22	18.4
Cost of Revenues [Member]
Employee Benefit Plans [Line Items]
Pension and post-retirement benefit expenses	10.6	9.5	10.7
Selling and Marketing [Member]
Employee Benefit Plans [Line Items]
Pension and post-retirement benefit expenses	6.7	6.7	6.8
Research and Development [Member]
Employee Benefit Plans [Line Items]
Pension and post-retirement benefit expenses	3.8	4	4
General and Administrative [Member]
Employee Benefit Plans [Line Items]
Pension and post-retirement benefit expenses	$ 1.5	$ 1.3	$ 1.6

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information 1 (Detail) - USD ($)

May 21, 2015

Sep. 19, 2014

Sep. 18, 2014

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Oct. 14, 2015

Oct. 26, 2016

Oct. 31, 2015

Oct. 28, 2015

Sep. 17, 2014

Feb. 04, 2014

Equity, Class of Treasury Stock [Line Items]

Treasury stock acquired

$ 150,461,000

$ 774,565,000

$ 716,782,000

Shares repurchases, value

$ 150,461,000

$ 774,565,000

$ 700,715,000

Common shares received

1,556,313

10,303,047

11,856,169

2014 Repurchase Program [Member]

Equity, Class of Treasury Stock [Line Items]

Repurchase program authorizing the purchase of shares

$ 850,000,000

$ 850,000,000

$ 300,000,000

Treasury stock acquired

$ 850,000,000

2014 Repurchase Program [Member] | September 2014 [Member]

Equity, Class of Treasury Stock [Line Items]

Shares repurchases, value

$ 300,000,000

Common shares received

1,200,000

4,500,000

Repurchased common shares, average purchase price paid per share

$ 52.79

Accelerated share repurchase agreement, description

On September 18, 2014, as part of the 2014 Repurchase Program, the Company entered into an ASR agreement to initiate share repurchases aggregating $300.0 million (the “September 2014 ASR Agreement”). As a result of the September 2014 ASR Agreement, the Company received approximately 4.5 million shares of MSCI’s common stock on September 19, 2014 and received approximately 1.2 million shares of MSCI’s common stock on May 21, 2015 for a combined average price of $52.79 per share.

2015 Repurchase Program [Member]

Equity, Class of Treasury Stock [Line Items]

Repurchase program authorizing the purchase of shares

$ 1,000,000,000

Stock repurchase program, remaining authorized repurchase amount

$ 330,300,000

2016 Repurchase Program [Member]

Equity, Class of Treasury Stock [Line Items]

Repurchase program authorizing the purchase of shares

$ 750,000,000

Stock repurchase program, remaining authorized repurchase amount

$ 733,100,000

Shareholders' Equity - Schedule

Shareholders' Equity - Schedule of Company's Common Stock Repurchases Pursuant to Open Market Repurchases (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Repurchased	1,556,313	10,303,047	11,856,169
Dollar Value of Shares Repurchased	$ 150,461	$ 774,565	$ 716,782
Open Market Purchases of Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Average Price Paid Per Share	$ 87.96	$ 73.71	$ 62.63
Total Number of Shares Repurchased	1,556,000	10,303,000	10,710,000
Dollar Value of Shares Repurchased	$ 136,899	$ 759,427	$ 670,824

Shareholders' Equity - Schedu52

Shareholders' Equity - Schedule of Cash Dividends Declared and Distributed Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Stockholders Equity [Abstract]
Dividend declared per common share	$ 0.38	$ 0.38	$ 0.28	$ 0.28	$ 0.28	$ 0.28	$ 0.22	$ 0.22	$ 0.22	$ 0.22	$ 0.18	$ 0.18	$ 1.32	$ 1	$ 0.80
Cash dividends declared, Amount	$ 34,745	$ 34,768	$ 25,710	$ 25,769	$ 26,524	$ 26,936	$ 21,588	$ 22,046	$ 22,803	$ 24,210	$ 20,444	$ 20,424	$ 120,992	$ 97,094	$ 87,881
Cash dividends distributed, Amount	34,448	34,403	25,444	25,500	26,304	26,680	21,391	21,889	22,792	24,152	20,442	20,411	119,795	96,264	87,797
Cash dividends deferred, Amount	$ 297	$ 365	$ 266	$ 269	$ 220	$ 256	$ 197	$ 157	$ 11	$ 58	$ 2	$ 13	$ 1,197	$ 830	$ 84

Shareholders' Equity - Summary

Shareholders' Equity - Summary of Activity Related to Shares of Common Stock Issued and Repurchased (Detail) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Common Stock Outstanding [Line Items]
Beginning balance	91,279,590	101,013,148	112,072,469
Dividend payable/paid	156	420	417
Common stock issued and exercise of stock options	538,499	788,304	1,558,965
Shares withheld for tax withholding and exercises	(158,090)	(219,921)	(763,558)
Shares repurchased under stock repurchase programs	(1,556,313)	(10,303,047)	(11,856,169)
Shares issued to directors	1,043	686	1,024
Ending balance	90,104,885	91,279,590	101,013,148
Common Stock Issued [Member]
Common Stock Outstanding [Line Items]
Beginning balance	128,996,344	128,200,189	126,637,390
Dividend payable/paid	156	892	802
Common stock issued and exercise of stock options	538,499	788,304	1,558,965
Shares issued to directors	8,857	6,959	3,032
Ending balance	129,543,856	128,996,344	128,200,189
Treasury Stock [Member]
Common Stock Outstanding [Line Items]
Beginning balance	(37,716,754)	(27,187,041)	(14,564,921)
Dividend payable/paid		(472)	(385)
Shares withheld for tax withholding and exercises	(158,090)	(219,921)	(763,558)
Shares repurchased under stock repurchase programs	(1,556,313)	(10,303,047)	(11,856,169)
Shares issued to directors	(7,814)	(6,273)	(2,008)
Ending balance	(39,438,971)	(37,716,754)	(27,187,041)

Shareholders' Equity - Additi54

Shareholders' Equity - Additional Information 2 (Detail) - USD ($)	Feb. 23, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares grants in period		0	0	0
Allocated share based compensation expense		$ 37,921,000	$ 32,525,000	$ 27,476,000
Tax benefits for share-based compensation expense related to deferred stock and stock options		5,500,000	7,400,000	15,300,000
Compensation cost related to unvested share-based awards not yet recognized		$ 29,900,000
Number of shares available for future grants		7,300,000
Total fair value of restricted stock units and restricted stock awards converted or vested to common stock		$ 30,300,000	39,400,000	34,100,000
Intrinsic value of the stock options exercised		$ 10,900,000	11,300,000	37,300,000
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation cost related to unvested share-based awards not yet recognized, period for recognition		1 year
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation cost related to unvested share-based awards not yet recognized, period for recognition		3 years
Income (loss) from Discontinued Operations, Net of Income Taxes [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Allocated share based compensation expense		$ 0	$ 0	$ 0
2017 Bonus Award [Member] | Subsequent Events [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares grants in period	211,144
Amount of the award granted to retirement-eligible employees	$ 2,400,000
Aggregate fair value	$ 26,600,000
2017 Bonus Award [Member] | Subsequent Events [Member] | RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period of awards	3 years
Fraction of bonus award vested per year	33.00%
2017 Bonus Award [Member] | Subsequent Events [Member] | MSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period of awards	3 years
Minimum performance period	3 years
Additional extended performance period	6 months

Shareholders' Equity - Componen

Shareholders' Equity - Components of Share-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	$ 37,921	$ 32,525	$ 27,476
Deferred Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	$ 37,921	$ 32,525	27,549
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense (benefit)			$ (73)

Shareholders' Equity - Summar56

Shareholders' Equity - Summary of Share-based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	$ 37,921	$ 32,525	$ 27,476
Cost of Revenues [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	9,707	7,971	6,909
Selling and Marketing [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	11,355	9,526	6,564
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	3,477	2,970	2,823
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	$ 13,382	$ 12,058	$ 11,180

Shareholders' Equity - Summar57

Shareholders' Equity - Summary of Vested and Unvested Deferred Stock Awards Activity (Detail) shares in Thousands	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Vested and unvested deferred stock awards at the beginning of period, Number of Shares | shares	1,507
Granted, Number of Shares | shares	302
Conversion to common stock, Number of Shares | shares	(351)
Canceled, Number of Shares | shares	(39)
Vested and unvested deferred stock awards at the end of period, Number of Shares | shares	1,419
Vested and unvested deferred stock awards at the beginning of period, Weighted Average Grant Date Fair Value | $ / shares	$ 61.82
Granted, Weighted Average Grant Date Fair Value | $ / shares	88.01
Conversion to common stock, Weighted Average Grant Date Fair Value | $ / shares	56.83
Canceled, Weighted Average Grant Date Fair Value | $ / shares	66.25
Vested and unvested deferred stock awards at the end of period, Weighted Average Grant Date Fair Value | $ / shares	$ 68.50

Shareholders' Equity - Summar58

Shareholders' Equity - Summary of Vested and Unvested Deferred Stock Awards Activity (Parenthetical) (Detail) shares in Thousands	Dec. 31, 2017$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Restricted stock units and restricted stock awards, vested or expected to vest | shares	1,366
Restricted stock units and restricted stock awards vested or expected to vest, weighted average price | $ / shares	$ 68.35

Shareholders' Equity - Summar59

Shareholders' Equity - Summary of Unvested Deferred Stock Awards Activity (Detail) shares in Thousands	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted Average Grant Date Fair Value, balance at the beginning of the period | $ / shares	$ 62.89
Weighted Average Grant Date Fair Value, Granted | $ / shares	88.27
Weighted Average Grant Date Fair Value, Vested | $ / shares	58.06
Weighted Average Grant Date Fair Value, Canceled | $ / shares	66.25
Weighted Average Grant Date Fair Value, balance at the end of the period | $ / shares	69.96
Weighted Average Grant Date Fair Value, Expected to vest | $ / shares	$ 69.84
Unvested Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested deferred stock awards, balance at the beginning of period | shares	1,207
Number of Shares, Granted | shares	277
Number of Shares, Vested | shares	(279)
Number of Shares, Canceled | shares	(39)
Unvested deferred stock awards, balance at the end of period | shares	1,166
Unvested deferred stock awards expected to vest | shares	1,113

Shareholders' Equity - Summar60

Shareholders' Equity - Summary of Stock Options Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options, Options outstanding, Beginning balance	269,000
Number of Options, Granted or assumed	0	0	0
Number of Options, Conversion to common stock	(124,000)
Number of Options, Options outstanding and exercisable, Ending balance	145,000
Weighted Average Exercise Price, Options outstanding, Beginning balance	$ 24.06
Weighted Average Exercise Price, Conversion to common stock	21.24
Weighted Average Exercise Price, Options outstanding and exercisable, Ending balance	$ 26.47
Weighted Average Remaining Life (Years), Options outstanding		2 years 2 months 19 days
Weighted Average Remaining Life (Years), Options outstanding and exercisable	2 years 1 month 9 days
Aggregated Intrinsic Value, Options outstanding and exercisable	$ 14,519

Shareholders' Equity - Summar61

Shareholders' Equity - Summary of Stock Options Outstanding and Exercisable by Exercise Price Range (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Number Outstanding, Options Outstanding and Exercisable | shares	145
Weighted Average Exercise Price, Options Outstanding and Exercisable	$ 26.47
Average Remaining Life (Years), Options Outstanding and Exercisable	2 years 1 month 9 days
Aggregate Intrinsic Value, Options Outstanding and Exercisable | $	$ 14,519
First Exercise Price Range [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Price, Minimum	$ 15.18
Range of Exercise Price, Maximum	$ 16.48
Number Outstanding, Options Outstanding and Exercisable | shares	38
Weighted Average Exercise Price, Options Outstanding and Exercisable	$ 16.47
Average Remaining Life (Years), Options Outstanding and Exercisable	1 year 1 month 24 days
Aggregate Intrinsic Value, Options Outstanding and Exercisable | $	$ 4,175
Second Exercise Price Range [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Price, Minimum	$ 20.45
Range of Exercise Price, Maximum	$ 24.11
Number Outstanding, Options Outstanding and Exercisable | shares	16
Weighted Average Exercise Price, Options Outstanding and Exercisable	$ 20.62
Average Remaining Life (Years), Options Outstanding and Exercisable	1 year 9 months 7 days
Aggregate Intrinsic Value, Options Outstanding and Exercisable | $	$ 1,733
Third Exercise Price Range [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices	$ 25.64
Number Outstanding, Options Outstanding and Exercisable | shares	41
Weighted Average Exercise Price, Options Outstanding and Exercisable	$ 25.64
Average Remaining Life (Years), Options Outstanding and Exercisable	2 years 1 month 9 days
Aggregate Intrinsic Value, Options Outstanding and Exercisable | $	$ 4,139
Fourth Exercise Price Range [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices	$ 36.70
Number Outstanding, Options Outstanding and Exercisable | shares	50
Weighted Average Exercise Price, Options Outstanding and Exercisable	$ 36.70
Average Remaining Life (Years), Options Outstanding and Exercisable	2 years 11 months 12 days
Aggregate Intrinsic Value, Options Outstanding and Exercisable | $	$ 4,472

Reclassifications out of Accu62

Reclassifications out of Accumulated Other Comprehensive Income (Loss) - Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Provision for income tax benefit	$ (62,358)	$ (35,650)	$ (36,245)	$ (28,674)	$ (28,845)	$ (32,241)	$ (33,587)	$ (30,410)	$ (162,927)	$ (125,083)	$ (119,516)
Net income	$ 64,602	$ 85,153	$ 81,266	$ 72,951	$ 68,250	$ 65,281	$ 66,957	$ 60,367	303,972	260,855	223,648
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Net income									(204)	(188)	(410)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) [Member] | Defined Benefit Pension Plans Amount Recognized as a Component of Net Periodic Benefit Expense [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Net periodic benefit expense for curtailments and settlements									(281)	(261)	(563)
Provision for income tax benefit									$ 77	$ 73	$ 153

Income Taxes - Summary of Provi

Income Taxes - Summary of Provision for Income Taxes (Benefits) by Taxing Jurisdiction (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Current, U.S. federal									$ 133,250	$ 93,071	$ 85,540
Current, U.S. state and local									16,312	16,363	22,108
Current, Non U.S.									32,267	32,616	22,156
Current provision for income taxes (benefits)									181,829	142,050	129,804
Deferred, U.S. federal									(12,502)	(13,010)	(10,546)
Deferred, U.S. state and local									(2,119)	(2,235)	1,460
Deferred, Non U.S.									(4,281)	(1,722)	(1,202)
Deferred provision for income taxes (benefits)									(18,902)	(16,967)	(10,288)
Provision for income taxes from continuing operations	$ 62,358	$ 35,650	$ 36,245	$ 28,674	$ 28,845	$ 32,241	$ 33,587	$ 30,410	$ 162,927	$ 125,083	119,516
Provision for income taxes from discontinued operations											$ 6,390

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Provision to U.S. Federal Statutory Income Tax Rate for Income from Continuing Operations (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
U.S. federal statutory income tax rate	35.00%	35.00%	35.00%
U.S. state and local income taxes, net of U.S. federal income tax benefits	1.84%	2.38%	4.44%
Change in tax rates applicable to non-U.S. earnings	(7.60%)	(3.73%)	(2.73%)
Domestic tax credits and incentives	(0.24%)	(0.26%)	(2.62%)
Net tax charge related to Tax Reform	7.40%
Excess Stock Based Compensation	(1.25%)
Other	(0.25%)	(0.98%)	0.10%
Effective income tax rate	34.90%	32.41%	34.19%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Examination [Line Items]
U.S. federal income tax rate reduction effective date	Jan. 1, 2018
Tax reform measurement period	1 year
Net charge to provision for income taxes	$ 34,500,000
Estimated tax charge related to toll charge	47,500,000
Estimated tax charge related to change in assertion	16,000,000
Estimated tax benefit related to revaluation of deferred tax assets	(29,000,000)
Estimated tax charge related to foreign withholding taxes	16,000,000
Earnings attributable to foreign subsidiaries	$ 450,700,000	$ 341,600,000	$ 224,800,000
Significant change in unrecognized tax benefits, reasonably possible	It is reasonably possible that significant changes in the balance of unrecognized tax benefits may occur within the next 12 months.
Significant change in unrecognized tax benefits, not possible	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.
Total amount of unrecognized tax benefits	$ 9,400,000
Unrecognized tax benefits, interest on income tax expense(benefit)	(200,000)
Penalties recognized during the year	0
Amount of accrued interest	$ 900,000
Minimum [Member]
Income Tax Examination [Line Items]
Tax years under examination	2,006
Maximum [Member]
Income Tax Examination [Line Items]
Tax years under examination	2,016
Capital Loss Carryforward [Member]
Income Tax Examination [Line Items]
Capital loss carryforward tax value	$ 10,600,000
Expiration period	2,019
Domestic Tax Authority [Member]
Income Tax Examination [Line Items]
Net operating loss carryforwards	$ 6,300,000
Expiration period	2,020
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member] | Minimum [Member] | Morgan Stanley [Member]
Income Tax Examination [Line Items]
Tax years under examination	2,006
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member] | Maximum [Member] | Morgan Stanley [Member]
Income Tax Examination [Line Items]
Tax years under examination	2,008
State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
Operating loss carryforwards, valuation allowance	$ 400,000
State and Local Jurisdiction [Member] | New York State Division of Taxation and Finance [Member] | Minimum [Member] | Morgan Stanley [Member]
Income Tax Examination [Line Items]
Tax years under examination	2,007
State and Local Jurisdiction [Member] | New York State Division of Taxation and Finance [Member] | Maximum [Member] | Morgan Stanley [Member]
Income Tax Examination [Line Items]
Tax years under examination	2,008
Foreign Tax Authority [Member]
Income Tax Examination [Line Items]
Net operating loss carryforwards	$ 1,300,000
Operating loss carryforwards, valuation allowance	600,000
Other Non-current Liabilities [Member]
Income Tax Examination [Line Items]
Estimated toll charge unrecognized	$ 43,600,000

Income Taxes - Significant Comp

Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Employee compensation and benefit plans	$ 19,646	$ 27,914
Deferred rent	5,308	7,869
Pension	1,520	1,965
Unearned revenue	853	1,322
Loss carryforwards - non-current	18,105	27,616
Other	1,435	558
Subtotal	46,867	67,244
Less: valuation allowance	(11,575)	(17,807)
Total deferred tax assets	35,292	49,437
Deferred tax liabilities:
Intangible assets	(73,634)	(121,900)
Investment in foreign subsidiaries	(16,108)
Property, equipment and leasehold improvements, net	(11,564)	(12,073)
Total deferred tax liabilities	(101,306)	(133,973)
Net deferred tax liabilities	$ (66,014)	$ (84,536)

Income Taxes - Summary of Defer

Income Taxes - Summary of Deferred Tax Asset Valuation Allowance (Detail) - Valuation Allowance of Deferred Tax Assets - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation And Qualifying Accounts Disclosure [Line Items]
Beginning balance	$ 17,807	$ 21,052	$ 21,232
Additions charged to cost and expenses	324	1,862
Deductions	(6,556)	(5,107)	(180)
Ending balance	$ 11,575	$ 17,807	$ 21,052

Income Taxes - Summary of Compo

Income Taxes - Summary of Components of Income Before Provision for Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Domestic									$ 283,779	$ 263,536	$ 282,764
Foreign									183,120	122,402	66,790
Income from continuing operations before provision for income taxes	$ 126,960	$ 120,803	$ 117,511	$ 101,625	$ 97,095	$ 97,522	$ 100,544	$ 90,777	$ 466,899	$ 385,938	$ 349,554

Income Taxes - Reconciliation69

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Beginning balance	$ 7,936	$ 8,692	$ 6,525
Increases based on tax positions related to the current period	3,389	575	536
Increases based on tax positions related to prior periods	519	135	2,131
Decreases based on tax positions related to prior periods	(6)	(3)	(500)
Decreases related to settlements with taxing authorities	(1,152)	(1,463)
Decreases related to a lapse of applicable statute of limitations	(664)
Ending balance	$ 10,022	$ 7,936	$ 8,692

Acquisitions And Dispositions -

Acquisitions And Dispositions - Additional Information (Detail) - USD ($) $ in Thousands	Oct. 16, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill		$ 1,560,621	$ 1,555,850	$ 1,565,621
Insignis [Member]
Business Acquisition [Line Items]
Company paid cash to acquire property	$ 6,500
Date of Acquisition	Oct. 16, 2015
Goodwill	$ 4,200
Purchase price allocated to identifiable intangible assets	2,200
Purchase price allocated for assets other than identifiable intangible assets	$ 100

Segment Information - Additiona

Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017Segment
Segment Reporting [Abstract]
Number of operating segments	4

Segment Information - Operating

Segment Information - Operating Revenue by Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating revenues	$ 334,779	$ 322,097	$ 316,089	$ 301,207	$ 292,812	$ 288,433	$ 290,596	$ 278,828	$ 1,274,172	$ 1,150,669	$ 1,075,013
Index [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating revenues									718,959	613,551	558,964
Analytics [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating revenues									458,269	448,353	433,424
All Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating revenues									$ 96,944	$ 88,765	$ 82,625

Segment Information - Segment P

Segment Information - Segment Profitability and Reconciliation to Net Income (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Adjusted EBITDA									$ 659,175	$ 569,457	$ 481,697
Amortization of intangible assets	$ 11,560	$ 10,614	$ 11,122	$ 11,251	$ 11,498	$ 11,752	$ 11,943	$ 11,840	44,547	47,033	46,910
Depreciation and amortization of property, equipment and leasehold improvements	8,118	9,325	9,159	8,838	9,447	8,312	8,393	8,168	35,440	34,320	30,889
Operating income	153,955	148,663	145,968	130,602	126,012	123,260	125,691	113,141	579,188	488,104	403,898
Other expense (income), net	26,995	27,860	28,457	28,977	28,917	25,738	25,147	22,364	112,289	102,166	54,344
Provision for income taxes	62,358	35,650	36,245	28,674	28,845	32,241	33,587	30,410	162,927	125,083	119,516
Income from continuing operations									303,972	260,855	230,038
Income (loss) from discontinued operations, net of income taxes											(6,390)
Net income	$ 64,602	$ 85,153	$ 81,266	$ 72,951	$ 68,250	$ 65,281	$ 66,957	$ 60,367	303,972	260,855	223,648
Index [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA									522,043	431,478	392,987
Analytics [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA									125,349	128,507	95,468
All Other [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA									$ 11,783	$ 9,472	$ (6,758)

Segment Information - Revenue b

Segment Information - Revenue by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues	$ 334,779	$ 322,097	$ 316,089	$ 301,207	$ 292,812	$ 288,433	$ 290,596	$ 278,828	$ 1,274,172	$ 1,150,669	$ 1,075,013
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues									622,132	556,777	519,429
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues									48,139	45,185	41,552
Total Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues									670,271	601,962	560,981
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues									193,831	175,749	166,019
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues									250,267	229,010	215,192
Europe, the Middle East and Africa ("EMEA") [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues									444,098	404,759	381,211
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues									54,351	52,161	45,371
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues									105,452	91,787	87,450
Total Asia & Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues									$ 159,803	$ 143,948	$ 132,821

Segment Information - Long-Live

Segment Information - Long-Lived Assets by Geographic Area (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 1,976,894	$ 1,999,075
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	1,847,605	1,876,366
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	1,685	1,543
Total Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	1,849,290	1,877,909
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	94,782	89,466
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	22,394	23,780
Total EMEA [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	117,176	113,246
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	432	357
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	9,996	7,563
Total Asia & Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 10,428	$ 7,920

Quarterly Results of Operatio76

Quarterly Results of Operations - Summary of Quarterly Results of Operations (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Operating revenues	$ 334,779	$ 322,097	$ 316,089	$ 301,207	$ 292,812	$ 288,433	$ 290,596	$ 278,828	$ 1,274,172	$ 1,150,669	$ 1,075,013
Cost of revenues	69,306	68,491	68,595	67,521	63,819	62,986	62,130	63,172	273,913	252,107	267,695
Selling and marketing	47,771	44,918	41,594	43,014	41,609	41,514	41,854	41,689	177,297	166,666	162,294
Research and development	20,721	17,983	18,203	18,977	18,960	18,750	18,566	18,928	75,884	75,204	77,320
General and administrative	23,348	22,103	21,448	21,004	21,467	21,859	22,019	21,890	87,903	87,235	86,007
Amortization of intangible assets	11,560	10,614	11,122	11,251	11,498	11,752	11,943	11,840	44,547	47,033	46,910
Depreciation and amortization of property, equipment and leasehold improvements	8,118	9,325	9,159	8,838	9,447	8,312	8,393	8,168	35,440	34,320	30,889
Total operating expenses	180,824	173,434	170,121	170,605	166,800	165,173	164,905	165,687	694,984	662,565	671,115
Operating income	153,955	148,663	145,968	130,602	126,012	123,260	125,691	113,141	579,188	488,104	403,898
Interest income	(2,237)	(1,835)	(1,310)	(932)	(901)	(799)	(585)	(621)	(6,314)	(2,906)	(1,166)
Interest expense	29,027	29,020	29,027	29,024	29,039	26,790	22,918	22,904	116,098	101,651	62,387
Other expense (income)	205	675	740	885	779	(253)	2,814	81	2,505	3,421	(6,877)
Other expense (income), net	26,995	27,860	28,457	28,977	28,917	25,738	25,147	22,364	112,289	102,166	54,344
Income from continuing operations before provision for income taxes	126,960	120,803	117,511	101,625	97,095	97,522	100,544	90,777	466,899	385,938	349,554
Provision for income taxes	62,358	35,650	36,245	28,674	28,845	32,241	33,587	30,410	162,927	125,083	119,516
Net income	$ 64,602	$ 85,153	$ 81,266	$ 72,951	$ 68,250	$ 65,281	$ 66,957	$ 60,367	$ 303,972	$ 260,855	$ 223,648
Earnings per basic common share	$ 0.72	$ 0.94	$ 0.90	$ 0.80	$ 0.73	$ 0.69	$ 0.69	$ 0.61	$ 3.36	$ 2.72	$ 2.05
Earnings per diluted common share	$ 0.70	$ 0.93	$ 0.89	$ 0.80	$ 0.73	$ 0.68	$ 0.69	$ 0.60	$ 3.31	$ 2.70	$ 2.03
Weighted average shares outstanding used in computing per share data
Basic	90,130	90,112	90,404	90,708	93,327	94,823	96,412	99,425	90,336	95,986	109,124
Diluted	92,467	91,868	91,708	91,624	93,845	95,473	96,888	99,998	91,914	96,540	109,926

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Jan. 30, 2018	Feb. 16, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Subsequent Event [Line Items]
Quarterly dividend declared			$ 0.38	$ 0.38	$ 0.28	$ 0.28	$ 0.28	$ 0.28	$ 0.22	$ 0.22	$ 0.22	$ 0.22	$ 0.18	$ 0.18	$ 1.32	$ 1	$ 0.80
Number of shares repurchased															1,556,313	10,303,047	11,856,169
Value of shares repurchased															$ 150,461	$ 774,565	$ 700,715
Subsequent Events [Member]
Subsequent Event [Line Items]
Quarterly dividend declared	$ 0.38
Quarterly dividend declared date	Jan. 30, 2018
Quarterly dividend payable date	Mar. 15, 2018
Quarterly dividend record date	Feb. 16, 2018
Number of shares repurchased		400,000
Average price per share		$ 137.06
Value of shares repurchased		$ 54,500