MarketAxess (MKTX) 10-K 25 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2015	Feb. 22, 2016	Jun. 30, 2015
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Trading Symbol	MKTX
Entity Registrant Name	MARKETAXESS HOLDINGS INC
Entity Central Index Key	1,278,021
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		37,522,515
Entity Public Float			$ 3.4

Consolidated Statements of Fina

Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Cash and cash equivalents	$ 199,728	$ 168,924
Securities available-for-sale, at fair value	84,706	64,863
Accounts receivable, net of allowance of $109 and $3 as of December 31, 2015 and December 31, 2014, respectively	40,459	33,836
Goodwill and intangible assets, net of accumulated amortization	64,142	66,419
Furniture, equipment, leasehold improvements and capitalized software, net of accumulated depreciation and amortization	30,897	32,185
Prepaid expenses and other assets	9,880	6,685
Deferred tax assets, net	9,229	6,972
Total assets	439,041	379,884
Liabilities
Accrued employee compensation	29,296	25,310
Income and other tax liabilities	4,463	5,940
Deferred revenue	2,312	2,465
Accounts payable, accrued expenses and other liabilities	12,257	11,961
Total liabilities	$ 48,328	$ 45,676
Commitments and Contingencies (Note 13)
Stockholders’ equity
Additional paid-in capital	$ 321,215	$ 307,059
Treasury stock - Common stock voting, at cost, 2,412,245 and 2,141,344 shares as of December 31, 2015 and December 31, 2014, respectively	(93,405)	(70,247)
Retained earnings	168,011	101,813
Accumulated other comprehensive loss	(5,229)	(4,537)
Total stockholders’ equity	390,713	334,208
Total liabilities and stockholders’ equity	$ 439,041	$ 379,884
Undefined Preferred Stock [Member]
Stockholders’ equity
Preferred stock
Series A Preferred Stock [Member]
Stockholders’ equity
Preferred stock
Voting Common Stock [Member]
Stockholders’ equity
Common stock	$ 121	$ 120

Consolidated Statements of Fin3

Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Allowance for accounts receivable	$ 109	$ 3
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	4,855,000	4,855,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.003	$ 0.003
Common stock, shares authorized	110,000,000	110,000,000
Common stock, shares issued	39,821,519	39,460,066
Common stock, shares outstanding	37,409,274	37,318,722
Treasury stock, shares	2,412,245	2,141,344
Series A Preferred Stock [Member]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	110,000	110,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common Stock Non-Voting [Member]
Common stock, par value	$ 0.003	$ 0.003
Common stock, shares authorized	10,000,000	10,000,000
Common stock, shares issued	0	0
Common stock, shares outstanding	0	0

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues
Commissions	$ 266,221	$ 221,138	$ 203,652
Information and post-trade services	30,660	31,510	25,377
Technology products and services	3,573	6,874	6,331
Investment income	905	543	420
Other	1,739	2,709	2,953
Total revenues	303,098	262,774	238,733
Expenses
Employee compensation and benefits	83,856	74,995	64,406
Depreciation and amortization	18,542	17,379	14,123
Technology and communications	15,916	17,685	16,037
Professional and consulting fees	13,043	14,375	18,220
Occupancy	4,685	4,381	5,173
Marketing and advertising	6,148	5,769	4,632
General and administrative	13,008	9,654	8,862
Total expenses	155,198	144,238	131,453
Income before income taxes from continuing operations	147,900	118,536	107,280
Provision for income taxes	51,863	43,730	38,717
Net income from continuing operations	96,037	74,806	68,563
Loss from discontinued operations, net of income taxes			(189)
Gain on the sale of discontinued operations, net of tax benefit			7,642
Net income	$ 96,037	$ 74,806	$ 76,016
Basic earnings per common share
Income from continuing operations	$ 2.62	$ 2.03	$ 1.86
Income from discontinued operations			0.20
Net income per common share	2.62	2.03	2.06
Diluted earnings per common share
Income from continuing operations	2.55	1.97	1.81
Income from discontinued operations			0.20
Net income per common share	2.55	1.97	2.01
Cash dividends declared per common share	$ 0.80	$ 0.64	$ 0.52
Weighted average shares outstanding
Basic	36,690	36,930	36,886
Diluted	37,637	37,889	37,888

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 96,037	$ 74,806	$ 76,016
Net cumulative translation adjustment and foreign currency exchange hedge, net of tax of $(258), $(275) and $(310), respectively	(512)	(399)	(537)
Net unrealized (loss) gain on securities available-for-sale, net of tax of $(111), $(9), and $14, respectively	(180)	(16)	21
Less: reclassification adjustment for realized gain on the sale of securities available-for-sale included in Other Income, net of tax of $(0), $(24) and $(299), respectively		(39)	(474)
Net changed in unrealized (loss) on securities available-for-sale, net of tax	(180)	(55)	(453)
Comprehensive Income	$ 95,345	$ 74,352	$ 75,026

Consolidated Statements of Com6

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]
Foreign currency exchange hedge, tax benefit	$ (258)	$ (275)	$ (310)
Securities available-for-sale, tax expense (benefit)	(111)	(9)	14
Sale of securities available- for-sale included in Other Income, tax benefit	$ 0	$ (24)	$ (299)

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock Voting [Member]	Additional Paid-in Capital [Member]	Treasury Stock - Common Stock Voting [Member]	Retained Earnings (Deficit) [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning Balance at Dec. 31, 2012	$ 242,717	$ 118	$ 283,609	$ (32,273)	$ (5,644)	$ (3,093)
Net income	76,016				76,016
Cumulative translation adjustment and foreign currency exchange hedge, net of tax	(537)					(537)
Unrealized net (loss) on securities available-for-sale, net of tax	(453)					(453)
Stock-based compensation	8,879		8,879
Exercise of stock options	3,039	1	3,038
Withholding tax payments on restricted stock vesting and stock option exercises	(5,001)		(5,001)
Excess tax benefits from stock-based compensation	5,032		5,032
Cash dividend on common stock	(19,330)				(19,330)
Ending Balance at Dec. 31, 2013	310,362	119	295,557	(32,273)	51,042	(4,083)
Net income	74,806				74,806
Cumulative translation adjustment and foreign currency exchange hedge, net of tax	(399)					(399)
Unrealized net (loss) on securities available-for-sale, net of tax	(55)					(55)
Stock-based compensation	9,769		9,769
Exercise of stock options	2,511	1	2,510
Withholding tax payments on restricted stock vesting and stock option exercises	(5,020)		(5,020)
Excess tax benefits from stock-based compensation	4,243		4,243
Repurchases of common stock	(37,974)			(37,974)
Cash dividend on common stock	(24,035)				(24,035)
Ending Balance at Dec. 31, 2014	334,208	120	307,059	(70,247)	101,813	(4,537)
Net income	96,037				96,037
Cumulative translation adjustment and foreign currency exchange hedge, net of tax	(512)					(512)
Unrealized net (loss) on securities available-for-sale, net of tax	(180)					(180)
Stock-based compensation	12,519		12,519
Exercise of stock options	1,824	1	1,823
Withholding tax payments on restricted stock vesting and stock option exercises	(4,496)		(4,496)
Excess tax benefits from stock-based compensation	4,310		4,310
Repurchases of common stock	(23,158)			(23,158)
Cash dividend on common stock	(29,839)				(29,839)
Ending Balance at Dec. 31, 2015	$ 390,713	$ 121	$ 321,215	$ (93,405)	$ 168,011	$ (5,229)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities
Net income	$ 96,037	$ 74,806	$ 76,016
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	18,542	17,379	13,051
Stock-based compensation expense	12,519	9,769	8,879
Deferred taxes	(2,424)	(374)	(1,331)
Gain on the sale of discontinued operations			(7,642)
Other	2,049	1,725	(296)
Changes in operating assets and liabilities:
Decrease (increase) in accounts receivable	(6,748)	827	(1,714)
Decrease (increase) in prepaid expenses and other assets	(2,662)	3,344	(1,846)
Increase in accrued employee compensation	3,986	1,309	4,010
(Decrease) increase in income and other tax liabilities	(941)	2,365	2,959
(Decrease) in deferred revenue	(153)	(248)	(1,571)
(Decrease) increase in accounts payable, accrued expenses and other liabilities	(9)	(950)	364
Net cash provided by operating activities	120,196	109,952	90,879
Cash flows from investing activities
Acquisition of business, net of cash acquired			(37,827)
Cash proceeds from the sale of discontinued operations, net of cash sold			9,346
Securities available-for-sale:
Proceeds from sales			30,900
Proceeds from maturities	35,248	17,574	12,515
Purchases	(57,175)	(16,423)	(60,755)
Purchases of furniture, equipment and leasehold improvements	(4,795)	(4,627)	(15,337)
Capitalization of software development costs	(10,589)	(10,160)	(7,945)
Other	(642)	611	(18)
Net cash (used in) investing activities	(37,953)	(13,025)	(69,121)
Cash flows from financing activities
Cash dividend on common stock	(29,534)	(23,941)	(19,837)
Exercise of stock options	1,824	2,511	3,039
Withholding tax payments on restricted stock vesting and stock option exercises	(4,496)	(5,020)	(5,001)
Excess tax benefits from stock-based compensation	4,310	4,243	5,032
Repurchases of common stock	(23,158)	(37,974)
Other		(42)	(307)
Net cash (used in) financing activities	(51,054)	(60,223)	(17,074)
Effect of exchange rate changes on cash and cash equivalents	(385)	(471)	(901)
Cash and cash equivalents
Net increase for the period	30,804	36,233	3,783
Beginning of period	168,924	132,691	128,908
End of period	199,728	168,924	132,691
Cash paid during the year
Cash paid for income taxes	$ 50,875	$ 33,627	30,768
Liabilities assumed in connection with the Xtrakter acquisition:
Fair value of assets acquired			44,791
Cash paid for the capital stock			(37,827)
Liabilities assumed			$ 6,964

Organization and Principal Busi

Organization and Principal Business Activity	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Organization and Principal Business Activity	1. Organization and Principal Business Activity MarketAxess Holdings Inc. (the “Company” or “MarketAxess”) was incorporated in the State of Delaware on April 11, 2000. Through its subsidiaries, the Company operates an electronic trading platform for corporate bonds and other types of fixed-income instruments through which the Company’s institutional investor clients can access liquidity provided by its broker-dealer and other institutional clients. The Company’s multi-dealer trading platform allows its institutional investor clients to simultaneously request competitive, executable bids or offers from multiple broker-dealers, and to execute trades with the broker-dealer of their choice. The Company’s trading platform provides access to global liquidity in U.S. high-grade corporate bonds, emerging markets and high-yield bonds, European bonds, U.S. agency bonds, credit derivatives and other fixed-income securities. The Company also executes certain bond transactions between and among institutional investor and broker-dealer clients on a matched principal basis by serving as counterparty to both the buyer and the seller in trades which then settle through a third-party clearing broker. The Company provides fixed-income market data, analytics and compliance tools that help its clients make trading decisions. The Company also provides trade matching and regulatory transaction reporting services to the securities markets. In addition, the Company provides technology solutions and professional consulting services to fixed-income industry participants.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Significant Accounting Policies	2. Significant Accounting Policies Basis of Presentation The consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany transactions and balances have been eliminated. Cash and Cash Equivalents Cash and cash equivalents includes cash and money market instruments that are primarily maintained at one major global bank. Given this concentration, the Company is exposed to certain credit risk in relation to its deposits at this bank. The Company defines cash equivalents as short-term interest-bearing investments with maturities at the time of purchase of three months or less. Securities Available-for-Sale The Company classifies its marketable securities as available-for-sale securities. Unrealized marketable securities gains and losses, net of taxes, are included in accumulated other comprehensive loss in the Consolidated Statements of Financial Condition. Realized gains and losses are recorded in the Consolidated Statements of Operations in other revenues. For the purpose of computing realized gains and losses, cost is determined on a specific identification basis. The Company assesses whether an other-than-temporary impairment loss on the investments has occurred due to declines in fair value or other market conditions. The portion of an other-than-temporary impairment related to credit loss is recorded as a charge in the Consolidated Statements of Operations. The remainder is recognized in accumulated other comprehensive loss if the Company does not intend to sell the security and it is more likely than not that the Company will not be required to sell the security prior to recovery. No charges for other-than-temporary losses were recorded during the years ended December 31, 2015, 2014 or 2013. Fair Value Financial Instruments Fair value is defined as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.” A three-tiered hierarchy for determining fair value has been established that prioritizes inputs to valuation techniques used in fair value calculations. The three levels of inputs are defined as Level 1 (unadjusted quoted prices for identical assets or liabilities in active markets), Level 2 (inputs that are observable in the marketplace other than those inputs classified in Level 1) and Level 3 (inputs that are unobservable in the marketplace). The Company’s financial assets and liabilities measured at fair value on a recurring basis consist of its money market funds, securities available-for-sale portfolio and foreign currency forward contracts. All other financial instruments are short-term in nature and the carrying amounts reported on the Consolidated Statements of Financial Condition approximate fair value. Allowance for Doubtful Accounts All accounts receivable have contractual maturities of less than one year and are derived from trading-related fees and commissions and revenues from products and services. The Company continually monitors collections and payments from its customers and maintains an allowance for doubtful accounts. The allowance for doubtful accounts is based upon the historical collection experience and specific collection issues that have been identified. Additions to the allowance for doubtful accounts are charged to bad debt expense, which is included in general and administrative expense in the Company’s Consolidated Statements of Operations. The allowance for doubtful accounts was $0.1 million, $0.0 million and $0.1 million as of December 31, 2015, 2014 and 2013, respectively. The provision for bad debts was $0.2 million, $0.1 million and $0.2 million for the years ended December 31, 2015, 2014 and 2013, respectively. Write-offs and other charges against the allowance for doubtful accounts were $0.1 million, $0.0 million and $0.1 million for the years ended December 31, 2015, 2014 and 2013, respectively. Depreciation and Amortization Fixed assets are carried at cost less accumulated depreciation. The Company uses the straight-line method of depreciation over three to seven years. The Company amortizes leasehold improvements on a straight-line basis over the lesser of the life of the improvement or the remaining term of the lease. Software Development Costs The Company capitalizes certain costs associated with the development of internal use software, including among other items, employee compensation and related benefits and third party consulting costs, at the point at which the conceptual formulation, design and testing of possible software project alternatives have been completed. Once the product is ready for its intended use, such costs are amortized on a straight-line basis over three years. The Company reviews the amounts capitalized for impairment whenever events or changes in circumstances indicate that the carrying amounts of the assets may not be recoverable. Cash Provided as Collateral Cash is provided as collateral for broker-dealer clearing accounts. Cash provided as collateral is included in prepaid expenses and other assets in the Consolidated Statements of Financial Condition. Foreign Currency Translation and Forward Contracts Assets and liabilities denominated in foreign currencies are translated using exchange rates at the end of the period; revenues and expenses are translated at average monthly rates. Gains and losses on foreign currency translation are a component of accumulated other comprehensive loss in the Consolidated Statements of Financial Condition. Transaction gains and losses are recorded in general and administrative expense in the Consolidated Statements of Operations. The Company enters into foreign currency forward contracts to hedge its net investment in its U.K. subsidiaries. Gains and losses on these transactions are included in accumulated other comprehensive loss in the Consolidated Statements of Financial Condition. Revenue Recognition The majority of the Company’s revenues are derived from commissions for trades executed on its platform and distribution fees that are billed to its broker-dealer clients on a monthly basis. The Company also derives revenues from information and post-trade services, technology products and services, investment income and other income. Commission revenue. Commissions are generally calculated as a percentage of the notional dollar volume of bonds traded on the platform and vary based on the type, size, yield and maturity of the bond traded. Under the Company’s transaction fee plans, bonds that are more actively traded or that have shorter maturities are generally charged lower commissions, while bonds that are less actively traded or that have longer maturities generally command higher commissions. For trades that the Company executes between and among institutional investor and broker-dealer clients on a matched principal basis by serving as counterparty to both the buyer and the seller, the Company earns the commission through the difference in price between the two matched principal trades. Fee programs for certain products include distribution fees which are recognized monthly. Information and post-trade services. The Company generates revenue from information services provided to our broker-dealer clients, institutional investor clients and data-only subscribers. Information services are invoiced monthly, quarterly or annually. When billed in advance, revenues are deferred and recognized monthly on a straight-line basis. The Company also generates revenue from regulatory transaction reporting and trade matching services. Revenue is recognized in the period the services are provided. Technology products and services. The Company generates revenues from professional consulting services, technology software licenses and maintenance and support services (referred to as post-contract technical support or “PCS”). Revenue is generally recognized when persuasive evidence of an arrangement exists, delivery has occurred, the fee is fixed or determinable and collection is considered probable. The Company enters into time and materials professional consulting contracts unrelated to any software product. Revenue for time and materials contracts is recognized as services are performed. The Company generally sells software license subscriptions on a stand-alone basis or software licenses and PCS together as part of multiple-element arrangements. Revenue for software license subscriptions is recognized ratably over the contract period. For arrangements that include multiple elements, generally software licenses and PCS, the Company allocates and defers revenue for the undelivered items based on vendor specific objective evidence (“VSOE”) of the fair value of the undelivered elements and recognizes the difference between the total arrangement fee and the amount deferred for the undelivered items as license revenue. When VSOE does not exist for undelivered items, the entire arrangement fee is recognized ratably over the performance period. For PCS, the term is typically one year and revenue is recognized over the duration of the arrangement on a straight-line basis. Initial set-up fees. The Company enters into agreements with its broker-dealer clients pursuant to which the Company provides access to its platform through a non-exclusive and non-transferable license. Broker-dealer clients may pay an initial set-up fee, which is typically due and payable upon execution of a broker-dealer agreement. The initial set-up fee, if any, varies by agreement. Revenue is recognized over the initial term of the agreement, which is generally two years. Initial set-up fees are reported in other income in the Consolidated Statements of Operations. Stock-Based Compensation The Company measures and recognizes compensation expense for all share-based payment awards based on their estimated fair values measured as of the grant date. These costs are recognized as an expense in the Consolidated Statements of Operations over the requisite service period, which is typically the vesting period, with an offsetting increase to additional paid-in capital. Income Taxes Income taxes are accounted for using the asset and liability method. 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. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance is recognized against deferred tax assets if it is more likely than not that such assets will not be realized in future years. The Company recognizes interest and penalties related to unrecognized tax benefits in general and administrative expenses in the Consolidated Statements of Operations. Business Combinations, Goodwill and Intangible Assets Business combinations are accounted for under the purchase method of accounting. The total cost of an acquisition is allocated to the underlying net assets based on their respective estimated fair values. The excess of the purchase price over the estimated fair values of the net assets acquired is recorded as goodwill. Determining the fair value of certain assets acquired and liabilities assumed is judgmental in nature and often involves the use of significant estimates and assumptions, including assumptions with respect to future cash flows, discount rates, growth rates and asset lives. The Company operates as a single reporting unit. Subsequent to an acquisition, goodwill no longer retains its identification with a particular acquisition, but instead becomes identifiable with the entire reporting unit. As a result, all of the fair value of the Company is available to support the value of goodwill. An impairment review of goodwill is performed on an annual basis, at year-end, or more frequently if circumstances change. Intangible assets with definite lives, including purchased technologies, customer relationships and other intangible assets, are amortized on a straight-line basis over their estimated useful lives, ranging from three to 15 years. Intangible assets are assessed for impairment when events or circumstances indicate the existence of a possible impairment. Earnings Per Share Basic earnings per share is computed by dividing the net income attributable to common stock by the weighted-average number of shares of common stock outstanding during the period. For purposes of computing diluted earnings per share, the weighted-average shares outstanding of common stock reflects the dilutive effect that could occur if convertible securities or other contracts to issue common stock were converted into or exercised for common stock. Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Out-of-Period Adjustment During the second quarter of 2013, the Company determined that it had incorrectly excluded incentive compensation as a component of employee compensation eligible for capitalization under its software development costs capitalization policy. The Company assessed this error and determined that it was not material to previous reporting periods and was not material to the year ended December 31, 2013. Therefore, the Company recorded this item as an out-of-period adjustment in the three months ended June 30, 2013 by reducing employee compensation and benefits expense by $2.9 million and increasing depreciation and amortization expense by $1.3 million in the Consolidated Statements of Operations and increasing the net book value of capitalized software by $1.6 million in the Consolidated Statements of Financial Condition. This item was reflected as a non-cash adjustment in the Consolidated Statements of Cash Flows for 2013. Recent Accounting Pronouncements In August 2015, the Financial Accounting Standards Board issued Accounting Standards Update (“ASU”) No. 2015-14, “Revenue from Contracts with Customers”, which will replace most of the existing revenue recognition guidance in GAAP. The core principle of the ASU is that an entity should recognize revenue for the transfer of goods or services equal to the amount that it expects to be entitled to receive for those goods or services. The ASU requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments. The ASU will be effective for the Company beginning January 1, 2018 and allows for both retrospective and prospective methods of adoption. The Company is in the process of determining the method of adoption and assessing the impact of this ASU on the Company’s Consolidated Financial Statements.

Net Capital Requirements

Net Capital Requirements	12 Months Ended
	Dec. 31, 2015
Net Capital [Abstract]
Net Capital Requirements	3. Net Capital Requirements Certain U.S. subsidiaries of the Company are registered as a broker-dealer or swap execution facility and therefore are subject to the applicable rules and regulations of the Securities and Exchange Commission and the Commodity Futures Trading Commission. These rules contain minimum net capital requirements, as defined in the applicable regulations, and also may require a significant part of the registrants’ assets be kept in relatively liquid form. Certain of the Company’s foreign subsidiaries are regulated by the Financial Conduct Authority in the U.K. or Ontario Securities Commission in Canada and must maintain financial resources, as defined in the applicable regulations, in excess of the applicable financial resources requirement. As of December 31, 2015, each of the Company’s subsidiaries that are subject to these regulations had net capital or financial resources in excess of their minimum requirements. As of December 31, 2015, the Company’s subsidiaries maintained aggregate net capital and financial resources that was $116.0 million in excess of the required levels of $9.4 million. Each of the Company’s U.S. and foreign regulated subsidiaries are subject to local regulations which generally prohibit repayment of borrowings from the Company or affiliates, paying cash dividends, making loans to the Company or affiliates or otherwise entering into transactions that result in a significant reduction in regulatory net capital or financial resources without prior notification to or approval from such regulated entity’s principal regulator.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements The following table summarizes the valuation of the Company’s assets and liabilities measured at fair value as categorized based on the hierarchy described in Note 2. Level 1 Level 2 Level 3 Total As of December 31, 2015 (In thousands) Money market funds $ 61,913 $ — $ — $ 61,913 Securities available-for-sale Corporate bonds — 82,671 — 82,671 Municipal securities — 2,035 — 2,035 Foreign currency forward position — 354 — 354 Total $ 61,913 $ 85,060 $ — $ 146,973 As of December 31, 2014 Money market funds $ 62,126 $ — $ — $ 62,126 Securities available-for-sale Corporate bonds — 53,167 — 53,167 Municipal securities — 11,696 — 11,696 Foreign currency forward position — 103 — 103 Total $ 62,126 $ 64,966 $ — $ 127,092 Securities classified within Level 2 were valued using a market approach utilizing prices and other relevant information generated by market transactions involving comparable assets. The foreign currency forward contracts are classified within Level 2 as the valuation inputs are based on quoted market prices. There were no financial assets classified within Level 3 during the years ended December 31, 2015 and 2014. The Company enters into foreign currency forward contracts to hedge the net investment in the Company’s U.K. subsidiaries. The Company designates each foreign currency forward contract as a hedge and assesses the risk management objective and strategy, including identification of the hedging instrument, the hedged item and the risk exposure and how effectiveness is to be assessed prospectively and retrospectively. These hedges are for a one-month period and are used to limit exposure to foreign currency exchange rate fluctuations. The fair value of the asset is included in accounts receivable and the fair value of the liability is included in accounts payable in the Consolidated Statements of Financial Condition. Gains or losses on foreign currency forward contracts designated as hedges are included in accumulated other comprehensive loss in the Consolidated Statements of Financial Condition. A summary of the foreign currency forward position is as follows: As of December 31, 2015 2014 (In thousands) Notional value $ 45,716 $ 32,089 Fair value of notional 45,362 31,986 Fair value of the asset $ 354 $ 103 The following is a summary of the Company’s securities available-for-sale: Gross Gross Estimated Amortized unrealized unrealized fair cost gains losses value (In thousands) As of December 31, 2015 Corporate bonds $ 82,937 $ 4 $ (270 ) $ 82,671 Municipal securities 2,035 — — 2,035 Total securities available-for-sale $ 84,972 $ 4 $ (270 ) $ 84,706 As of December 31, 2014 Corporate bonds $ 53,146 $ 50 $ (29 ) $ 53,167 Municipal securities 11,693 5 (2 ) 11,696 Total securities available-for-sale $ 64,839 $ 55 $ (31 ) $ 64,863 The following table summarizes the contractual maturities of securities available-for-sale: As of December 31, 2015 2014 (In thousands) Less than one year $ 37,694 $ 36,062 Due in 1 - 5 years 47,012 28,801 Total securities available-for-sale $ 84,706 $ 64,863 Proceeds from the sales and maturities of securities available-for-sale during the years ended December 31, 2015, 2014 and 2013 were $35.2 million, $17.6 million and $43.4 million, respectively. The following table provides fair values and unrealized losses on securities available-for-sale that have been in a continuous unrealized loss position for less than 12 months: Less than Twelve Months Twelve Months or More Total Estimated Gross Estimated Gross Estimated Gross fair unrealized fair unrealized fair unrealized value losses value losses value losses (In thousands) As of December 31, 2015 Corporate bonds $ 70,651 $ (270 ) $ — $ — $ 70,651 $ (270 ) Total $ 70,651 $ (270 ) $ — $ — $ 70,651 $ (270 ) As of December 31, 2014 Corporate bonds $ 20,487 $ (29 ) $ — $ — $ 20,487 $ (29 ) Municipal securities 2,139 (2 ) — — 2,139 (2 ) Total $ 22,626 $ (31 ) $ — $ — $ 22,626 $ (31 )

Acquisition

Acquisition	12 Months Ended
	Dec. 31, 2015
Business Combinations [Abstract]
Acquisition	5. Acquisition In February 2013, the Company acquired all of the outstanding shares of Xtrakter Limited (“Xtrakter”) from Euroclear S.A./N.V. Xtrakter is a U.K.-based provider of trade matching and regulatory transaction reporting for European securities and market and reference data across a range of fixed-income products. The acquisition of Xtrakter provides the Company with an expanded set of technology solutions ahead of incoming pre-and post-trade transparency requirements from the Markets in Financial Instruments Directive II in Europe. The aggregate purchase price was $37.8 million in cash, net of acquired cash. The Company has completed its allocation of the purchase price to the fair value of assets acquired and liabilities assumed at the date of acquisition. The purchase price allocation is as follows (in thousands): Purchase price $ 46,683 Less: acquired cash (8,856 ) Purchase price, net of acquired cash 37,827 Accounts receivable 3,733 Intangible assets 13,255 Other assets 1,718 Deferred tax liability, net (2,342 ) Accounts payable, accrued expenses and deferred revenue (4,622 ) Goodwill $ 26,085 The acquired intangible assets are as follows (in thousands, except for useful lives): Costs Useful Lives Customer relationships $ 5,455 10-15 years Internally developed software 5,000 3 years Tradename- indefinite life 1,820 indefinite Tradename- finite life 300 3 years Non-compete agreement 380 3 years Other 300 indefinite Total $ 13,255 The identifiable intangible assets and goodwill are not deductible for tax purposes. From the date of acquisition to December 31, 2013, Xtrakter-related revenue and net loss of $18.4 million and $0.9 million, respectively, have been included in the Company’s Consolidated Statements of Operations. The following unaudited pro forma consolidated financial information reflects the results of continuing operations of the Company for the year ended December 31, 2013, as if the acquisition of Xtrakter had occurred as of the beginning of the year presented, after giving effect to certain purchase accounting adjustments. These pro forma results are not necessarily indicative of what the Company’s operating results would have been had the acquisition actually taken place at the beginning of each period presented. The pro forma financial information includes the amortization charges from acquired intangible assets, adjustments to interest income to reflect the cash purchase price and related tax effects. Pro forma Year Ended December 31, 2013 (In thousands, except per share amounts) (unaudited) Revenues $ 242,657 Income before income taxes $ 107,316 Net income $ 68,579 Basic net income per common share $ 1.86 Diluted net income per common share $ 1.81

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	6. Goodwill and Intangible Assets Goodwill and intangible assets with indefinite lives was $59.7 million as of both December 31, 2015 and 2014. Intangible assets that are subject to amortization, including the related accumulated amortization, are comprised of the following: December 31, 2015 December 31, 2014 Cost Accumulated Amortization Net Carrying Amount Cost Accumulated Amortization Net Carrying Amount (In thousands) Technology $ 5,770 $ (5,492 ) $ 278 $ 5,770 $ (3,826 ) $ 1,944 Customer relationships 5,668 (1,553 ) 4,115 5,682 (1,183 ) 4,499 Non-competition agreements 380 (359 ) 21 380 (232 ) 148 Tradenames 370 (353 ) 17 370 (253 ) 117 Total $ 12,188 $ (7,757 ) $ 4,431 $ 12,202 $ (5,494 ) $ 6,707 Amortization expense associated with identifiable intangible assets was $2.3 million, $2.3 million and $2.2 million, respectively, for the years ended December 31, 2015, 2014 and 2013. Estimated total amortization expense is $0.7 million for 2016 and $0.4 million for each of 2017, 2018, 2019 and 2020.

Capitalized Software, Furniture

Capitalized Software, Furniture, Equipment and Leasehold Improvements	12 Months Ended
	Dec. 31, 2015
Property Plant And Equipment [Abstract]
Capitalized Software, Furniture, Equipment and Leasehold Improvements	7. Capitalized Software, Furniture, Equipment and Leasehold Improvements Capitalized software development costs, furniture, equipment and leasehold improvements, net of accumulated depreciation and amortization, are comprised of the following: As of December 31, 2015 2014 (In thousands) Software development costs $ 60,724 $ 50,327 Computer hardware and related software 26,328 25,513 Office hardware 3,414 2,785 Furniture and fixtures 1,955 1,921 Leasehold improvements 8,457 8,128 100,878 88,674 Accumulated depreciation and amortization (69,981 ) (56,489 ) Total $ 30,897 $ 32,185 During the years ended December 31, 2015 and 2014, software development costs totaling $10.6 million and $10.2, respectively, were capitalized. Non-capitalized software costs and routine maintenance costs are expensed as incurred and are included in employee compensation and benefits and professional and consulting fees in the Consolidated Statements of Operations.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	8. Income Taxes The provision for income taxes from continuing operations consists of the following: Year Ended December 31, 2015 2014 2013 (In thousands) Current: Federal $ 38,357 $ 31,700 $ 26,071 State and local 7,180 6,505 5,958 Foreign 4,346 1,456 1,014 Total current provision 49,883 39,661 33,043 Deferred: Federal 1,492 3,583 5,507 State and local 299 530 812 Foreign 189 (44 ) (645 ) Total deferred provision 1,980 4,069 5,674 Provision for income taxes $ 51,863 $ 43,730 $ 38,717 Pre-tax income from U.S. operations was $126.4 million, $112.5 million and $105.2 million for the years ended December 31, 2015, 2014 and 2013, respectively. Pre-tax income from foreign operations was $21.5 million, $6.0 million and $2.1 million for the years ended December 31, 2015, 2014 and 2013, respectively. The difference between the Company’s reported provision for income taxes and the U.S. federal statutory rate of 35% is as follows: Year Ended December 31, 2015 2014 2013 U.S. federal tax at statutory rate 35.0 % 35.0 % 35.0 % State and local taxes - net of federal benefit 3.4 4.2 4.1 Credits and deductions related to research activities (1.3 ) (1.7 ) (3.0 ) Foreign rate differential benefit (2.0 ) (0.6 ) (0.3 ) Other, net — — 0.3 Provision for income taxes 35.1 % 36.9 % 36.1 % The following is a summary of the Company’s net deferred tax assets: As of December 31, 2015 2014 (In thousands) Deferred tax assets U.S. net operating loss carryforwards $ 2,580 $ 3,102 Capital loss carryforwards 7,294 7,428 Stock compensation expense 9,115 7,266 Other 3,745 3,482 Total deferred tax assets 22,734 21,278 Valuation allowance (7,294 ) (7,428 ) Net deferred tax assets 15,440 13,850 Deferred tax liabilities Depreciation and amortization (1,953 ) (2,461 ) Capitalized software development costs (4,344 ) (4,495 ) Intangible assets (1,310 ) (1,854 ) Deferred tax assets, net $ 7,833 $ 5,040 As of December 31, 2015, the Company had deferred tax assets associated with stock-based compensation of approximately $9.1 million. There is a risk that the ultimate tax benefit realized upon the exercise of stock options or vesting of restricted stock could be less than the tax benefit previously recognized and exhaust the additional-paid-in-capital pool. If this should occur, any excess tax benefit previously recognized would be reversed, resulting in an increase in tax expense. Since the tax benefit to be realized in the future is unknown, it is not currently possible to estimate the impact on the deferred tax balance. As of December 31, 2015, the additional paid-in-capital pool, which is determined under a one pool approach for employee and non-employee awards, was approximately $56.9 million. The additional paid-in-capital pool is currently sufficient to absorb a complete write-off of the stock-based compensation deferred tax asset. In 2001 and 2000, MarketAxess Holdings Inc. and MarketAxess Corporation had an ownership change within the meaning of Section 382 of the Internal Revenue Code. As of December 31, 2015, the Company had restricted U.S. federal net operating loss carryforwards of approximately $6.7 million, which begin to expire in 2021. The Company’s net operating loss carryforwards may be subject to additional annual limitations if there is a 50% or greater change in the Company’s ownership, as determined over a rolling three-year period. As of December 31, 2015, the Company had state net operating loss carryforwards of approximately $4.4 million which expire in 2017. The ultimate realization of deferred income tax assets is dependent upon the generation of future taxable income during the periods in which the temporary differences become deductible. If it is not more likely than not that some portion or all of the gross deferred income tax assets will be realized in future years, a valuation allowance is recorded. As of December 31, 2015, the valuation allowance relates to certain capital loss carryforwards that are not expected to be realized. In October 2013, the Company recognized a $20.6 million capital loss on the sale of Greenline Financial Technologies, Inc. (“Greenline”) (See Note 14, “Discontinued Operations”) of which $1.2 million was carried back or otherwise utilized against current period capital gains. A full valuation allowance was provided against the remaining capital loss carryforward. A summary of the changes in the valuation allowance is as follows: Year Ended December 31, 2015 2014 2013 (In thousands) Valuation allowance at beginning of year $ 7,428 $ 7,743 $ 727 (Decrease) increase to valuation allowance attributable to: Current year income — (101 ) (65 ) State net operating loss — (155 ) (406 ) Blended state rate changes (71 ) — — Capital (loss) gain (63 ) (59 ) 7,487 Valuation allowance at end of year $ 7,294 $ 7,428 $ 7,743 The Company or one of its subsidiaries files U.S. federal, state and foreign income tax returns. Income tax returns for New York City (through 2003) and state (through 2009) and Connecticut state (through 2003) tax returns have been audited. Examinations of the Company’s federal tax return for 2011 and 2012 and New York state franchise tax returns for 2010 through 2013 are currently underway. The Company cannot estimate when the examinations will conclude or the impact such examinations will have on the Company’s Consolidated Financial Statements, if any. A reconciliation of the unrecognized tax benefits is as follows: Year Ended December 31, 2015 2014 2013 (In thousands) Balance at beginning of year $ 265 $ 265 $ 49 Additions for tax positions of current year — — 235 Reductions for tax positions of prior years — — (19 ) Balance at end of year $ 265 $ 265 $ 265 The Company has determined that unremitted earnings of its foreign subsidiaries will be considered indefinitely reinvested outside of the United States. No provision has been made for income tax on approximately $27.0 million of undistributed earnings of foreign subsidiaries at December 31, 2015. If these earnings were repatriated to the United States or no longer determined to be indefinitely reinvested outside the United States, the deferred tax liability associated with such earnings would have been approximately $3.3 million.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Stockholders' Equity	9. Stockholders’ Equity Common Stock As of December 31, 2015 and 2014, the Company had 110,000,000 authorized shares of voting common stock and 10,000,000 authorized shares of non-voting common stock. Voting common stock entitles the holder to one vote per share of common stock held. The following is a summary of the change in the Company’s outstanding shares of voting common stock: Year Ended December 31, 2015 2014 2013 (In thousands) Outstanding shares of voting common stock at the beginning of year 37,319 37,729 37,407 Exercise of stock options 183 120 256 Issuance of restricted stock, net of shares withheld for tax payments and cancellations 178 116 66 Repurchases (271 ) (646 ) — Outstanding shares of voting common stock at the end of year 37,409 37,319 37,729 In January 2014, the Board of Directors of the Company authorized a share repurchase program for up to $35.0 million of the Company’s common stock. In July 2014, the Board of Directors increased the authorization under the share repurchase program by an additional $65.0 million of the Company’s common stock. The share repurchase program will expire on February 29, 2016. In January 2016, the Board of Directors authorized a new two-year share repurchase program for up to $25.0 million of the Company’s common stock. Shares repurchased under the programs will be held in treasury for future use. Dividends

Stock-Based Compensation Plans

Stock-Based Compensation Plans	12 Months Ended
	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation Plans	10. Stock-Based Compensation Plans The Company has a stock incentive plan which provides for the grant of stock options, stock appreciation rights, restricted stock, performance shares, performance units, or other stock-based awards as incentives and rewards to encourage employees, consultants and non-employee directors to participate in the long-term success of the Company. As of December 31, 2015, there were 612,857 shares available for grant under the stock incentive plan. Total stock-based compensation expense was as follows: Year Ended December 31, 2015 2014 2013 (In thousands) Employee: Restricted stock and performance shares $ 10,792 $ 8,193 $ 7,269 Stock options 826 676 900 11,618 8,869 8,169 Non-employee directors: Restricted stock 901 900 710 Total stock-based compensation $ 12,519 $ 9,769 $ 8,879 The Company records stock-based compensation expense for employees in employee compensation and benefits and for non-employee directors in general and administrative expenses in the Consolidated Statements of Operations. Stock Options The exercise price of each option granted is equal to the market price of the Company’s common stock on the date of grant. Generally, option grants have provided for vesting over a three or five-year period. Options generally expire in ten years from the date of grant. The fair value of each option award is estimated on the date of grant using the Black-Scholes option-pricing model. The determination of fair value of share-based payment awards on the date of grant using an option-pricing model is affected by the Company’s stock price as well as assumptions regarding a number of highly complex and subjective variables, including the expected stock price volatility over the term of the awards, the risk-free interest rate, the expected dividend yield rate and the expected term. Expected volatilities are based on historical volatility of the Company’s stock. The risk-free interest rate is based on U.S. Treasury securities with a maturity value approximating the expected term of the option. The dividend yield rate is based on the expected annual dividends to be paid divided by the expected stock price. The expected term represents the period of time that options granted are expected to be outstanding based on actual and projected employee stock option exercise behavior. The weighted-average fair value for options granted during 2015, 2014 and 2013 was $36.46, $19.25 and $19.61, respectively. The following table represents the assumptions used for the Black-Scholes option-pricing model to determine the per share weighted-average fair value for options granted for the three years ended December 31, 2015: 2015 2014 2013 Expected life (years) 7.0 5.0 9.9 Risk-free interest rate 1.9 % 1.7 % 1.9 % Expected volatility 56.7 % 35.5 % 44.3 % Expected dividend yield 1.1 % 1.0 % 1.2 % In addition to the option grants above, the Company granted 119,981 stock options to the Company’s Chief Executive Officer in January 2015 which expire in 5.5 years from the grant date. Subject to the Chief Executive Officer’s continued employment with the Company through the applicable vesting date, one-third of the options under the option award will vest and become exercisable on each of January 15, 2018, 2019 and 2020. The fair value of the option award as of the date of the grant was $2.0 million as determined by an independent third party using a Monte Carlo simulation model. Key assumptions used for the Monte Carlo pricing model included an exercise price of $88.25 (125% of the market price on the date of the grant), a risk free interest rate of 1.4%, volatility of 27.3% and a dividend yield of 0.9%. The following table reports stock option activity during the three years ended December 31, 2015 and the intrinsic value as of December 31, 2015: Weighted- Remaining Number of Average Contractual Shares Exercise Price ($) Term Intrinsic Value ($) (In thousands) Outstanding at December 31, 2012 1,429,822 13.62 Granted 51,597 41.75 Canceled (4,348 ) 33.84 Exercised (256,622 ) 12.33 Outstanding at December 31, 2013 1,220,449 15.01 Granted 382 63.07 Canceled (41,071 ) 41.47 Exercised (165,340 ) 15.85 Outstanding at December 31, 2014 1,014,420 13.81 Granted 120,650 88.15 Canceled - Exercised (196,034 ) 11.60 15,312 Outstanding at December 31, 2015 939,036 23.83 2.9 82,412 Exercisable at December 31, 2015 790,471 14.07 2.6 77,084 The intrinsic value is the amount by which the closing price of the Company’s common stock on December 31, 2015 of $111.59 or the price on the day of exercise exceeds the exercise price of the stock options multiplied by the number of shares. As of December 31, 2015, there was $1.5 million of total unrecognized compensation cost related to non-vested stock options. That cost is expected to be recognized over a weighted-average period of 3.3 years. Restricted Stock and Performance Shares Restricted stock generally vests over a three or five-year period. Compensation expense is measured at the grant date and recognized ratably over the vesting period. Performance share awards are granted to certain senior managers. Each performance share award is earned or forfeited based on the level of achievement by the Company of pre-tax operating income on a per share basis before performance share and cash bonus expense. The pay-out ranges from zero to 150% of the performance share award. For each performance share earned, a participant is awarded an equal number of shares of restricted stock. Any restricted stock awarded to a participant vests and ceases to be restricted stock in two equal installments on each of the second and third anniversaries of the date of grant of the applicable performance share award. Compensation expense for performance shares is measured at the grant date and recognized on a graded basis over the vesting period. The pay-out achievement was 130%, 85.0%, and 108.0% of the performance award for 2015, 2014 and 2013, respectively. The following table reports performance share activity for the three years ended December 31, 2015: Performance year 2015 2014 2013 Share pay-out at plan 28,520 29,678 42,908 Actual share pay-out in following year 37,076 25,228 46,340 Weighted average fair value per share on grant date $ 70.60 $ 63.07 $ 35.98 In addition to the grants above, the Company granted a 116,659 performance stock award to the Company’s Chief Executive Officer in January 2015. The performance stock award provides that the number of performance shares earned by the Chief Executive Officer will be based on the Company’s achievement of certain performance levels. Subject to the Chief Executive Officer’s continued employment, if only the minimum performance level is achieved, then 35,463 performance shares will vest 100% on January 15, 2020, and if any performance level above the minimum level is achieved then the performance shares will vest 50% on each of January 15, 2019 and January 15, 2020. Certain performance levels above the minimum level were achieved during 2015. As a result, 92,419 shares of the performance stock award were earned and will vest 50% on each of January 15, 2019 and January 15, 2020. The fair value of the performance stock award as of the date of the grant was $6 million as determined by an independent third party using a Monte Carlo simulation model. Key assumptions used for the Monte Carlo pricing model included a risk free interest rate of 1.3%, volatility of 27.3% and a dividend yield of 0.9%. The following table reports restricted stock and performance share activity during the three years ended December 31, 2015: Weighted-Average Number of Grant Date Fair Restricted Shares Value Outstanding at December 31, 2012 751,259 $ 21.88 Granted 255,266 Performance share pay-out 41,481 Canceled (93,358 ) Vested (384,914 ) Outstanding at December 31, 2013 569,734 $ 31.86 Granted 149,349 Performance share pay-out 46,340 Canceled (43,185 ) Vested (286,249 ) Outstanding at December 31, 2014 435,989 $ 41.83 Granted 210,087 Performance share pay-out 25,228 Canceled (3,845 ) Vested (235,321 ) Outstanding at December 31, 2015 432,138 $ 56.24 As of December 31, 2015, there was $16.5 million of total unrecognized compensation expense related to non-vested restricted stock and performance shares. That cost is expected to be recognized over a weighted-average period of 1.9 years. Employee Stock Purchase Plan During 2015, the Company established a non-qualified employee stock purchase plan for non-executive employees. Under the plan, participants are granted the right to purchase shares of common stock based on the fair market value on the last day of the six-month offering period. On the purchase date, the Company will grant to the participants a number of shares of common stock equal to 20% of the aggregate shares purchased by the participant. These matching shares vest over a one-year period. For the year ended December 31, 2015, the Company did not issue any matching shares in connection with the plan but recognized

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Earnings Per Share	11. Earnings Per Share The following table sets forth the computation of basic and diluted earnings per common share: Year Ended December 31, 2015 2014 2013 (In thousands, except per share amounts) Net income from continuing operations $ 96,037 $ 74,806 $ 68,563 Net income from discontinued operations — — 7,453 Net income $ 96,037 $ 74,806 $ 76,016 Basic weighted average shares outstanding 36,690 36,930 36,886 Dilutive effect of stock options and restricted stock 947 959 1,002 Diluted weighted average shares outstanding 37,637 37,889 37,888 Basic earnings per common share Income from continuing operations $ 2.62 $ 2.03 $ 1.86 Income from discontinued operations — — 0.20 Basic earnings per share $ 2.62 $ 2.03 $ 2.06 Diluted earnings per common share Income from continuing operations $ 2.55 $ 1.97 $ 1.81 Income from discontinued operations — — 0.20 Diluted earnings per share $ 2.55 $ 1.97 $ 2.01 Stock options and restricted stock totaling 128,383 shares, 66,637 shares and 160,838 shares for the years ended December 31, 2015, 2014 and 2013, respectively, were excluded from the computation of diluted earnings per share because their effect would have been antidilutive. The computation of diluted shares can vary among periods due, in part, to the change in the average price of the Company’s common stock.

Credit Agreement

Credit Agreement	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Credit Agreement	12. Credit Agreement In January 2013, the Company entered into a three-year credit agreement that provided for revolving loans and letters of credit up to an aggregate of $50.0 million. In October 2015, the company entered into an amended and restated credit agreement (the “Credit Agreement”) increasing the borrowing capacity to an aggregate of $100.0 million, including a $5.0 million sub-limit for standby letters of credit. The Credit Agreement will mature in October 2017. As of December 31, 2015, the Company had $1.1 million in letters of credit outstanding leaving $98.9 million available to borrow under the Credit Agreement. Subject to satisfaction of certain specified conditions, the Company is permitted to upsize the borrowing capacity under the Credit Agreement by an additional $50.0 million. Borrowings under the Credit Agreement will bear interest at a rate per annum equal to either of the following, as designated by the Company for each borrowing: (A) the sum of (i) the greatest of (a) the prime rate, as defined, (b) the federal funds effective rate plus 0.50% and (c) one month adjusted LIBOR plus 1.00% plus (ii) 0.50% or (B) the sum of (i) adjusted LIBOR plus (ii) 1.50%. Default interest is 2.00% per annum in excess of the rate otherwise applicable in the case of any overdue principal or any other overdue amount. The Company is also required to pay a commitment fee to the lenders under the Credit Agreement in respect of unutilized revolving loan commitments at a rate of 0.40% per annum. The Company’s existing and future domestic subsidiaries (other than any broker-dealer subsidiary) have guaranteed the Company’s obligations under the Credit Agreement. Subject to customary exceptions and exclusions, the Company’s borrowings under the Credit Agreement are collateralized by first priority pledges (subject to permitted liens) of substantially all of the Company’s personal property assets and the personal property assets of the Company’s domestic subsidiaries that have guaranteed the Credit Agreement, including the equity interests of the Company’s domestic subsidiaries and the equity interests of certain of the Company’s foreign subsidiaries (limited, in the case of the voting equity interests of the foreign subsidiaries, to a pledge of 65% of those equity interests). The Credit Agreement requires that the Company’s consolidated total leverage ratio tested on the last day of each fiscal quarter not exceed 2.5 to 1.0 and a consolidated interest coverage ratio tested on the last day of each fiscal quarter not be less than 3.5 to 1.0. The Credit Agreement also requires that the Company’s trailing twelve month adjusted EBITDA tested on the last day of each fiscal quarter not be less than $80 million. The Company was in compliance with all applicable covenants at December 31, 2015 and 2014. If an event of default occurs, including failure to pay principal or interest due on the loan balance, a voluntary or involuntary proceeding seeking liquidation, change in control of the Company, or one or more material judgments against the Company in excess of $10.0 million, the lenders would be entitled to accelerate the borrowings under the Credit Agreement and take various other actions, including all actions permitted to be taken by a secured creditor. If certain bankruptcy events of default occur, the borrowings under the Credit Agreement will automatically accelerate.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2015
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	13. Commitments and Contingencies Lease Commitments The Company leases office space under non-cancelable lease agreements expiring at various dates through 2027. Office space leases are subject to escalation based on certain costs incurred by the landlord. Minimum rental commitments as of December 31, 2015 under such operating leases were as follows (in thousands): 2016 $ 3,395 2017 3,319 2018 3,042 2019 2,866 2020 2,866 2021 and thereafter 8,678 $ 24,166 Rental expense for the years ended December 31, 2015, 2014 and 2013 was $4.1 million, $3.8 million and $3.8 million, respectively, and is included in occupancy expense in the Consolidated Statements of Operations. Rental expense has been recorded based on the total minimum lease payments after giving effect to rent abatement and concessions, which are being amortized on a straight-line basis over the life of the lease. The Company is contingently obligated for standby letters of credit amounting to $1.1 million that were issued to landlords for office space. The Company has assigned a lease agreement on a leased property to a third party and is contingently liable should the assignee default on future lease obligations through the November 2020 lease termination date. The aggregate amount of the future lease obligation under this arrangement is $1.4 million as of December 31, 2015. Legal In the normal course of business, the Company and its subsidiaries included in the consolidated financial statements may be involved in various lawsuits, proceedings and regulatory examinations. The Company assesses its liabilities and contingencies in connection with outstanding legal proceedings, if any, utilizing the latest information available. For matters where it is probable that the Company will incur a material loss and the amount can be reasonably estimated, the Company would establish an accrual for the loss. Once established, the accrual would be adjusted to reflect any relevant developments. When a loss contingency is not both probable and estimable, the Company does not establish an accrual. Based on currently available information, the outcome of the Company’s outstanding matters is not expected to have a material adverse impact on the Company’s financial position. It is not presently possible to determine the ultimate exposure to these matters and there is no assurance that the resolution of the outstanding matters will not significantly exceed any reserves accrued by the Company. Other The Company, through two regulated subsidiaries, executes certain bond transactions between and among institutional investor and broker-dealer clients on a matched principal basis by serving as counterparty to both the buyer and the seller in trades which settle through third-party clearing brokers. Settlement typically occurs within one to three trading days after the trade date. Cash settlement of the transaction occurs upon receipt or delivery of the underlying instrument that was traded. For the years ended December 31, 2015, 2014 and 2013, revenues from matched principal trading were approximately $16.9 million, $7.4 million and $6.0 million, respectively. Under securities clearing agreements with a third party clearing broker, the Company maintains collateral deposits with the clearing broker in the form of cash. As of December 31, 2015, the amount of the collateral deposits included in prepaid expenses and other assets in the Consolidated Statements of Financial Condition was $1.5 million. For the years ended December 31, 2015, 2014 and 2013, clearing expenses associated with matched principal transactions were $3.3 million, $1.3 million and $0.9 million, respectively, and are classified under general and administrative expense on the Consolidated Statements of Operations. The Company is exposed to credit risk in the event a counterparty does not fulfill its obligation to complete a transaction or if there is a miscommunication or other error in executing a matched principal transaction. Pursuant to the terms of the securities clearing agreements, the clearing broker has the right to charge the Company for losses resulting from a counterparty’s failure to fulfill its contractual obligations. The losses are not capped at a maximum amount and apply to all trades executed through the clearing broker. At December 31, 2015 and 2014, the Company had not recorded any liabilities with regard to this right. In the normal course of business, the Company enters into contracts that contain a variety of representations, warranties and general indemnifications. The Company’s maximum exposure under these arrangements is unknown, as this would involve future claims that may be made against the Company that have not yet occurred. However, based on experience, the Company expects the risk of loss to be remote.

Discontinued Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2015
Discontinued Operations And Disposal Groups [Abstract]
Discontinued Operations	14. Discontinued Operations In October 2013, the Company sold 100% of the outstanding shares of Greenline, a wholly owned subsidiary of the Company, to CameronTec Intressenter AB. The aggregate purchase price was $11.0 million in cash, including a post-closing working capital adjustment. The Company recognized a gain on the disposition of $7.6 million, net of a tax benefit. Greenline’s operating results have been classified as discontinued operations in the Consolidated Statement of Operations. The following is a summary of Greenline’s operating results: Year Ended December 31, 2013 (In thousands) Revenues $ 6,137 Expenses 6,384 Loss before income taxes and gain on the sale from discontinued operations (247 ) Benefit for income taxes (58 ) Gain on the sale of discontinued operations, net of tax benefit 7,642 Income from discontinued operations $ 7,453

Segment and Geographic Informat

Segment and Geographic Information	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Segment and Geographic Information	15. Segment and Geographic Information The Company operates an electronic multi-party platform for the trading of fixed-income securities and provides related data, analytics, compliance tools and post-trade services. The Company’s operations constitute a single business segment because of the highly integrated nature of these product and services, of the financial markets in which the Company competes and of the Company’s worldwide business activities. The Company believes that results by geographic region or client sector are not necessarily meaningful in understanding its business. For the years ended December 31, 2015, 2014 and 2013, the U.K. was the only individual foreign country in which the Company had a subsidiary that accounted for 10% or more of the total revenues or total long-lived assets. Revenues and long-lived assets are attributed to geographic area based on the location of the particular subsidiary. Long-lived assets are defined as furniture, equipment, leasehold improvements and capitalized software Year Ended December 31, 2015 2014 2013 (In thousands) Revenues United States $ 262,558 $ 223,741 $ 207,519 United Kingdom 39,338 38,189 30,722 Other 1,202 844 492 Total $ 303,098 $ 262,774 $ 238,733 As of December 31, 2015 2014 (In thousands) Long-lived assets, as defined United States $ 21,968 $ 23,099 United Kingdom 8,910 9,057 Other 19 29 Total $ 30,897 $ 32,185

Deferred Compensation Plans

Deferred Compensation Plans	12 Months Ended
	Dec. 31, 2015
Compensation And Retirement Disclosure [Abstract]
Deferred Compensation Plans	16. Deferred Compensation Plans The Company, through its U.S. and U.K. subsidiaries, offers its employees the opportunity to invest in defined contribution plans. For the years ended December 31, 2015, 2014 and 2013, the Company contributed $1.9 million, $1.8 million and $1.7 million, respectively, to the plans. In 2015, the Company adopted a non-qualified deferred cash incentive plan for certain officers and other employees. Under the plan, eligible employees may defer up to 100% of their annual cash incentive pay. The Company has elected to fund its deferred compensation obligations through a rabbi trust. The rabbi trust is subject to creditor claims in the event of insolvency but such assets are not available for general corporate purposes. Assets held in the rabbi trust are invested in mutual funds, as selected by the participants, which are designated as trading securities and carried at fair value. The initial deferrals occurred in January 2016. Trading gains and losses on securities held in the rabbi trust will be included in other revenues and offsetting increases or decreases in the deferred compensation obligation will be recorded in employee compensation and benefits.

Customer Concentration

Customer Concentration	12 Months Ended
	Dec. 31, 2015
Risks And Uncertainties [Abstract]
Customer Concentration	17. Customer Concentration During the years ended December 31, 2015, 2014 and 2013, no single client accounted for more than 10% of total revenue. One institutional investor client accounted for approximately 15.3%, 14.0% and 12.5% of trading volumes during the years ended December 31, 2015, 2014 and 2013, respectively. As of December 31, 2015, investment funds managed by this institutional investor client beneficially owned approximately 8.9% of the outstanding shares of the Company’s common stock, primarily through passive index and ETF funds.

Significant Accounting Polici26

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany transactions and balances have been eliminated.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents includes cash and money market instruments that are primarily maintained at one major global bank. Given this concentration, the Company is exposed to certain credit risk in relation to its deposits at this bank. The Company defines cash equivalents as short-term interest-bearing investments with maturities at the time of purchase of three months or less.
Securities Available-for-Sale	Securities Available-for-Sale The Company classifies its marketable securities as available-for-sale securities. Unrealized marketable securities gains and losses, net of taxes, are included in accumulated other comprehensive loss in the Consolidated Statements of Financial Condition. Realized gains and losses are recorded in the Consolidated Statements of Operations in other revenues. For the purpose of computing realized gains and losses, cost is determined on a specific identification basis. The Company assesses whether an other-than-temporary impairment loss on the investments has occurred due to declines in fair value or other market conditions. The portion of an other-than-temporary impairment related to credit loss is recorded as a charge in the Consolidated Statements of Operations. The remainder is recognized in accumulated other comprehensive loss if the Company does not intend to sell the security and it is more likely than not that the Company will not be required to sell the security prior to recovery. No charges for other-than-temporary losses were recorded during the years ended December 31, 2015, 2014 or 2013.
Fair Value Financial Instruments	Fair Value Financial Instruments Fair value is defined as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.” A three-tiered hierarchy for determining fair value has been established that prioritizes inputs to valuation techniques used in fair value calculations. The three levels of inputs are defined as Level 1 (unadjusted quoted prices for identical assets or liabilities in active markets), Level 2 (inputs that are observable in the marketplace other than those inputs classified in Level 1) and Level 3 (inputs that are unobservable in the marketplace). The Company’s financial assets and liabilities measured at fair value on a recurring basis consist of its money market funds, securities available-for-sale portfolio and foreign currency forward contracts. All other financial instruments are short-term in nature and the carrying amounts reported on the Consolidated Statements of Financial Condition approximate fair value.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts All accounts receivable have contractual maturities of less than one year and are derived from trading-related fees and commissions and revenues from products and services. The Company continually monitors collections and payments from its customers and maintains an allowance for doubtful accounts. The allowance for doubtful accounts is based upon the historical collection experience and specific collection issues that have been identified. Additions to the allowance for doubtful accounts are charged to bad debt expense, which is included in general and administrative expense in the Company’s Consolidated Statements of Operations. The allowance for doubtful accounts was $0.1 million, $0.0 million and $0.1 million as of December 31, 2015, 2014 and 2013, respectively. The provision for bad debts was $0.2 million, $0.1 million and $0.2 million for the years ended December 31, 2015, 2014 and 2013, respectively. Write-offs and other charges against the allowance for doubtful accounts were $0.1 million, $0.0 million and $0.1 million for the years ended December 31, 2015, 2014 and 2013, respectively.
Depreciation and Amortization	Depreciation and Amortization Fixed assets are carried at cost less accumulated depreciation. The Company uses the straight-line method of depreciation over three to seven years. The Company amortizes leasehold improvements on a straight-line basis over the lesser of the life of the improvement or the remaining term of the lease.
Software Development Costs	Software Development Costs The Company capitalizes certain costs associated with the development of internal use software, including among other items, employee compensation and related benefits and third party consulting costs, at the point at which the conceptual formulation, design and testing of possible software project alternatives have been completed. Once the product is ready for its intended use, such costs are amortized on a straight-line basis over three years. The Company reviews the amounts capitalized for impairment whenever events or changes in circumstances indicate that the carrying amounts of the assets may not be recoverable.
Cash Provided as Collateral	Cash Provided as Collateral Cash is provided as collateral for broker-dealer clearing accounts. Cash provided as collateral is included in prepaid expenses and other assets in the Consolidated Statements of Financial Condition.
Foreign Currency Translation and Forward Contracts	Foreign Currency Translation and Forward Contracts Assets and liabilities denominated in foreign currencies are translated using exchange rates at the end of the period; revenues and expenses are translated at average monthly rates. Gains and losses on foreign currency translation are a component of accumulated other comprehensive loss in the Consolidated Statements of Financial Condition. Transaction gains and losses are recorded in general and administrative expense in the Consolidated Statements of Operations. The Company enters into foreign currency forward contracts to hedge its net investment in its U.K. subsidiaries. Gains and losses on these transactions are included in accumulated other comprehensive loss in the Consolidated Statements of Financial Condition.
Revenue Recognition	Revenue Recognition The majority of the Company’s revenues are derived from commissions for trades executed on its platform and distribution fees that are billed to its broker-dealer clients on a monthly basis. The Company also derives revenues from information and post-trade services, technology products and services, investment income and other income. Commission revenue. Commissions are generally calculated as a percentage of the notional dollar volume of bonds traded on the platform and vary based on the type, size, yield and maturity of the bond traded. Under the Company’s transaction fee plans, bonds that are more actively traded or that have shorter maturities are generally charged lower commissions, while bonds that are less actively traded or that have longer maturities generally command higher commissions. For trades that the Company executes between and among institutional investor and broker-dealer clients on a matched principal basis by serving as counterparty to both the buyer and the seller, the Company earns the commission through the difference in price between the two matched principal trades. Fee programs for certain products include distribution fees which are recognized monthly. Information and post-trade services. The Company generates revenue from information services provided to our broker-dealer clients, institutional investor clients and data-only subscribers. Information services are invoiced monthly, quarterly or annually. When billed in advance, revenues are deferred and recognized monthly on a straight-line basis. The Company also generates revenue from regulatory transaction reporting and trade matching services. Revenue is recognized in the period the services are provided. Technology products and services. The Company generates revenues from professional consulting services, technology software licenses and maintenance and support services (referred to as post-contract technical support or “PCS”). Revenue is generally recognized when persuasive evidence of an arrangement exists, delivery has occurred, the fee is fixed or determinable and collection is considered probable. The Company enters into time and materials professional consulting contracts unrelated to any software product. Revenue for time and materials contracts is recognized as services are performed. The Company generally sells software license subscriptions on a stand-alone basis or software licenses and PCS together as part of multiple-element arrangements. Revenue for software license subscriptions is recognized ratably over the contract period. For arrangements that include multiple elements, generally software licenses and PCS, the Company allocates and defers revenue for the undelivered items based on vendor specific objective evidence (“VSOE”) of the fair value of the undelivered elements and recognizes the difference between the total arrangement fee and the amount deferred for the undelivered items as license revenue. When VSOE does not exist for undelivered items, the entire arrangement fee is recognized ratably over the performance period. For PCS, the term is typically one year and revenue is recognized over the duration of the arrangement on a straight-line basis. Initial set-up fees. The Company enters into agreements with its broker-dealer clients pursuant to which the Company provides access to its platform through a non-exclusive and non-transferable license. Broker-dealer clients may pay an initial set-up fee, which is typically due and payable upon execution of a broker-dealer agreement. The initial set-up fee, if any, varies by agreement. Revenue is recognized over the initial term of the agreement, which is generally two years. Initial set-up fees are reported in other income in the Consolidated Statements of Operations.
Stock-Based Compensation	Stock-Based Compensation The Company measures and recognizes compensation expense for all share-based payment awards based on their estimated fair values measured as of the grant date. These costs are recognized as an expense in the Consolidated Statements of Operations over the requisite service period, which is typically the vesting period, with an offsetting increase to additional paid-in capital.
Income Taxes	Income Taxes Income taxes are accounted for using the asset and liability method. 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. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance is recognized against deferred tax assets if it is more likely than not that such assets will not be realized in future years. The Company recognizes interest and penalties related to unrecognized tax benefits in general and administrative expenses in the Consolidated Statements of Operations.
Business Combinations, Goodwill and Intangible Assets	Business Combinations, Goodwill and Intangible Assets Business combinations are accounted for under the purchase method of accounting. The total cost of an acquisition is allocated to the underlying net assets based on their respective estimated fair values. The excess of the purchase price over the estimated fair values of the net assets acquired is recorded as goodwill. Determining the fair value of certain assets acquired and liabilities assumed is judgmental in nature and often involves the use of significant estimates and assumptions, including assumptions with respect to future cash flows, discount rates, growth rates and asset lives. The Company operates as a single reporting unit. Subsequent to an acquisition, goodwill no longer retains its identification with a particular acquisition, but instead becomes identifiable with the entire reporting unit. As a result, all of the fair value of the Company is available to support the value of goodwill. An impairment review of goodwill is performed on an annual basis, at year-end, or more frequently if circumstances change. Intangible assets with definite lives, including purchased technologies, customer relationships and other intangible assets, are amortized on a straight-line basis over their estimated useful lives, ranging from three to 15 years. Intangible assets are assessed for impairment when events or circumstances indicate the existence of a possible impairment.
Earnings Per Share	Earnings Per Share Basic earnings per share is computed by dividing the net income attributable to common stock by the weighted-average number of shares of common stock outstanding during the period. For purposes of computing diluted earnings per share, the weighted-average shares outstanding of common stock reflects the dilutive effect that could occur if convertible securities or other contracts to issue common stock were converted into or exercised for common stock.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Out-of-Period Adjustment	Out-of-Period Adjustment During the second quarter of 2013, the Company determined that it had incorrectly excluded incentive compensation as a component of employee compensation eligible for capitalization under its software development costs capitalization policy. The Company assessed this error and determined that it was not material to previous reporting periods and was not material to the year ended December 31, 2013. Therefore, the Company recorded this item as an out-of-period adjustment in the three months ended June 30, 2013 by reducing employee compensation and benefits expense by $2.9 million and increasing depreciation and amortization expense by $1.3 million in the Consolidated Statements of Operations and increasing the net book value of capitalized software by $1.6 million in the Consolidated Statements of Financial Condition. This item was reflected as a non-cash adjustment in the Consolidated Statements of Cash Flows for 2013.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In August 2015, the Financial Accounting Standards Board issued Accounting Standards Update (“ASU”) No. 2015-14, “Revenue from Contracts with Customers”, which will replace most of the existing revenue recognition guidance in GAAP. The core principle of the ASU is that an entity should recognize revenue for the transfer of goods or services equal to the amount that it expects to be entitled to receive for those goods or services. The ASU requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments. The ASU will be effective for the Company beginning January 1, 2018 and allows for both retrospective and prospective methods of adoption. The Company is in the process of determining the method of adoption and assessing the impact of this ASU on the Company’s Consolidated Financial Statements.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Valuation of Company's Assets and Liabilities Measured at Fair Value	The following table summarizes the valuation of the Company’s assets and liabilities measured at fair value as categorized based on the hierarchy described in Note 2. Level 1 Level 2 Level 3 Total As of December 31, 2015 (In thousands) Money market funds $ 61,913 $ — $ — $ 61,913 Securities available-for-sale Corporate bonds — 82,671 — 82,671 Municipal securities — 2,035 — 2,035 Foreign currency forward position — 354 — 354 Total $ 61,913 $ 85,060 $ — $ 146,973 As of December 31, 2014 Money market funds $ 62,126 $ — $ — $ 62,126 Securities available-for-sale Corporate bonds — 53,167 — 53,167 Municipal securities — 11,696 — 11,696 Foreign currency forward position — 103 — 103 Total $ 62,126 $ 64,966 $ — $ 127,092
Summary of Foreign Currency Forward Contracts	A summary of the foreign currency forward position is as follows: As of December 31, 2015 2014 (In thousands) Notional value $ 45,716 $ 32,089 Fair value of notional 45,362 31,986 Fair value of the asset $ 354 $ 103
Summary of Company's Securities Available-for-Sale	The following is a summary of the Company’s securities available-for-sale: Gross Gross Estimated Amortized unrealized unrealized fair cost gains losses value (In thousands) As of December 31, 2015 Corporate bonds $ 82,937 $ 4 $ (270 ) $ 82,671 Municipal securities 2,035 — — 2,035 Total securities available-for-sale $ 84,972 $ 4 $ (270 ) $ 84,706 As of December 31, 2014 Corporate bonds $ 53,146 $ 50 $ (29 ) $ 53,167 Municipal securities 11,693 5 (2 ) 11,696 Total securities available-for-sale $ 64,839 $ 55 $ (31 ) $ 64,863
Summary of Contractual Maturities of Securities Available-for-Sale	The following table summarizes the contractual maturities of securities available-for-sale: As of December 31, 2015 2014 (In thousands) Less than one year $ 37,694 $ 36,062 Due in 1 - 5 years 47,012 28,801 Total securities available-for-sale $ 84,706 $ 64,863
Fair Values and Unrealized Losses on Securities Available-for-Sale	The following table provides fair values and unrealized losses on securities available-for-sale that have been in a continuous unrealized loss position for less than 12 months: Less than Twelve Months Twelve Months or More Total Estimated Gross Estimated Gross Estimated Gross fair unrealized fair unrealized fair unrealized value losses value losses value losses (In thousands) As of December 31, 2015 Corporate bonds $ 70,651 $ (270 ) $ — $ — $ 70,651 $ (270 ) Total $ 70,651 $ (270 ) $ — $ — $ 70,651 $ (270 ) As of December 31, 2014 Corporate bonds $ 20,487 $ (29 ) $ — $ — $ 20,487 $ (29 ) Municipal securities 2,139 (2 ) — — 2,139 (2 ) Total $ 22,626 $ (31 ) $ — $ — $ 22,626 $ (31 )

Acquisition (Tables)

Acquisition (Tables)	12 Months Ended
	Dec. 31, 2015
Business Combinations [Abstract]
Preliminary Purchase Price Allocation	The Company has completed its allocation of the purchase price to the fair value of assets acquired and liabilities assumed at the date of acquisition. The purchase price allocation is as follows (in thousands): Purchase price $ 46,683 Less: acquired cash (8,856 ) Purchase price, net of acquired cash 37,827 Accounts receivable 3,733 Intangible assets 13,255 Other assets 1,718 Deferred tax liability, net (2,342 ) Accounts payable, accrued expenses and deferred revenue (4,622 ) Goodwill $ 26,085
Summary of Acquired Intangible Assets	The acquired intangible assets are as follows (in thousands, except for useful lives): Costs Useful Lives Customer relationships $ 5,455 10-15 years Internally developed software 5,000 3 years Tradename- indefinite life 1,820 indefinite Tradename- finite life 300 3 years Non-compete agreement 380 3 years Other 300 indefinite Total $ 13,255
Pro forma Financial Information	The pro forma financial information includes the amortization charges from acquired intangible assets, adjustments to interest income to reflect the cash purchase price and related tax effects. Pro forma Year Ended December 31, 2013 (In thousands, except per share amounts) (unaudited) Revenues $ 242,657 Income before income taxes $ 107,316 Net income $ 68,579 Basic net income per common share $ 1.86 Diluted net income per common share $ 1.81

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Company's Intangible Assets	Goodwill and intangible assets with indefinite lives was $59.7 million as of both December 31, 2015 and 2014. Intangible assets that are subject to amortization, including the related accumulated amortization, are comprised of the following: December 31, 2015 December 31, 2014 Cost Accumulated Amortization Net Carrying Amount Cost Accumulated Amortization Net Carrying Amount (In thousands) Technology $ 5,770 $ (5,492 ) $ 278 $ 5,770 $ (3,826 ) $ 1,944 Customer relationships 5,668 (1,553 ) 4,115 5,682 (1,183 ) 4,499 Non-competition agreements 380 (359 ) 21 380 (232 ) 148 Tradenames 370 (353 ) 17 370 (253 ) 117 Total $ 12,188 $ (7,757 ) $ 4,431 $ 12,202 $ (5,494 ) $ 6,707

Capitalized Software, Furnitu30

Capitalized Software, Furniture, Equipment and Leasehold Improvements (Tables)	12 Months Ended
	Dec. 31, 2015
Property Plant And Equipment [Abstract]
Capitalized Software Development Costs, Furniture, Equipment and Leasehold Improvements, Net of Accumulated Depreciation and Amortization	Capitalized software development costs, furniture, equipment and leasehold improvements, net of accumulated depreciation and amortization, are comprised of the following: As of December 31, 2015 2014 (In thousands) Software development costs $ 60,724 $ 50,327 Computer hardware and related software 26,328 25,513 Office hardware 3,414 2,785 Furniture and fixtures 1,955 1,921 Leasehold improvements 8,457 8,128 100,878 88,674 Accumulated depreciation and amortization (69,981 ) (56,489 ) Total $ 30,897 $ 32,185

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Schedule of Provision for Income Taxes	The provision for income taxes from continuing operations consists of the following: Year Ended December 31, 2015 2014 2013 (In thousands) Current: Federal $ 38,357 $ 31,700 $ 26,071 State and local 7,180 6,505 5,958 Foreign 4,346 1,456 1,014 Total current provision 49,883 39,661 33,043 Deferred: Federal 1,492 3,583 5,507 State and local 299 530 812 Foreign 189 (44 ) (645 ) Total deferred provision 1,980 4,069 5,674 Provision for income taxes $ 51,863 $ 43,730 $ 38,717
Difference Between the Company's Reported Provision for Income Taxes and the U.S. Federal Statutory Rate	The difference between the Company’s reported provision for income taxes and the U.S. federal statutory rate of 35% is as follows: Year Ended December 31, 2015 2014 2013 U.S. federal tax at statutory rate 35.0 % 35.0 % 35.0 % State and local taxes - net of federal benefit 3.4 4.2 4.1 Credits and deductions related to research activities (1.3 ) (1.7 ) (3.0 ) Foreign rate differential benefit (2.0 ) (0.6 ) (0.3 ) Other, net — — 0.3 Provision for income taxes 35.1 % 36.9 % 36.1 %
Summary of Company's Net Deferred Tax Assets	The following is a summary of the Company’s net deferred tax assets: As of December 31, 2015 2014 (In thousands) Deferred tax assets U.S. net operating loss carryforwards $ 2,580 $ 3,102 Capital loss carryforwards 7,294 7,428 Stock compensation expense 9,115 7,266 Other 3,745 3,482 Total deferred tax assets 22,734 21,278 Valuation allowance (7,294 ) (7,428 ) Net deferred tax assets 15,440 13,850 Deferred tax liabilities Depreciation and amortization (1,953 ) (2,461 ) Capitalized software development costs (4,344 ) (4,495 ) Intangible assets (1,310 ) (1,854 ) Deferred tax assets, net $ 7,833 $ 5,040
Summary of Changes in Valuation Allowance	A summary of the changes in the valuation allowance is as follows: Year Ended December 31, 2015 2014 2013 (In thousands) Valuation allowance at beginning of year $ 7,428 $ 7,743 $ 727 (Decrease) increase to valuation allowance attributable to: Current year income — (101 ) (65 ) State net operating loss — (155 ) (406 ) Blended state rate changes (71 ) — — Capital (loss) gain (63 ) (59 ) 7,487 Valuation allowance at end of year $ 7,294 $ 7,428 $ 7,743
Reconciliation of the Unrecognized Tax Benefits	A reconciliation of the unrecognized tax benefits is as follows: Year Ended December 31, 2015 2014 2013 (In thousands) Balance at beginning of year $ 265 $ 265 $ 49 Additions for tax positions of current year — — 235 Reductions for tax positions of prior years — — (19 ) Balance at end of year $ 265 $ 265 $ 265

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Summary of the Change in the Company's Outstanding Shares of Common Stock	The following is a summary of the change in the Company’s outstanding shares of voting common stock: Year Ended December 31, 2015 2014 2013 (In thousands) Outstanding shares of voting common stock at the beginning of year 37,319 37,729 37,407 Exercise of stock options 183 120 256 Issuance of restricted stock, net of shares withheld for tax payments and cancellations 178 116 66 Repurchases (271 ) (646 ) — Outstanding shares of voting common stock at the end of year 37,409 37,319 37,729

Stock-Based Compensation Plans

Stock-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation Expense	Total stock-based compensation expense was as follows: Year Ended December 31, 2015 2014 2013 (In thousands) Employee: Restricted stock and performance shares $ 10,792 $ 8,193 $ 7,269 Stock options 826 676 900 11,618 8,869 8,169 Non-employee directors: Restricted stock 901 900 710 Total stock-based compensation $ 12,519 $ 9,769 $ 8,879
Assumptions Used for the Black-Scholes Option-Pricing Model to Determine the Per Share Weighted Average Fair Value for Options Granted	The following table represents the assumptions used for the Black-Scholes option-pricing model to determine the per share weighted-average fair value for options granted for the three years ended December 31, 2015: 2015 2014 2013 Expected life (years) 7.0 5.0 9.9 Risk-free interest rate 1.9 % 1.7 % 1.9 % Expected volatility 56.7 % 35.5 % 44.3 % Expected dividend yield 1.1 % 1.0 % 1.2 %
Stock Option Activity	The following table reports stock option activity during the three years ended December 31, 2015 and the intrinsic value as of December 31, 2015: Weighted- Remaining Number of Average Contractual Shares Exercise Price ($) Term Intrinsic Value ($) (In thousands) Outstanding at December 31, 2012 1,429,822 13.62 Granted 51,597 41.75 Canceled (4,348 ) 33.84 Exercised (256,622 ) 12.33 Outstanding at December 31, 2013 1,220,449 15.01 Granted 382 63.07 Canceled (41,071 ) 41.47 Exercised (165,340 ) 15.85 Outstanding at December 31, 2014 1,014,420 13.81 Granted 120,650 88.15 Canceled - Exercised (196,034 ) 11.60 15,312 Outstanding at December 31, 2015 939,036 23.83 2.9 82,412 Exercisable at December 31, 2015 790,471 14.07 2.6 77,084
Summary of Performance of Share Activity	The following table reports performance share activity for the three years ended December 31, 2015: Performance year 2015 2014 2013 Share pay-out at plan 28,520 29,678 42,908 Actual share pay-out in following year 37,076 25,228 46,340 Weighted average fair value per share on grant date $ 70.60 $ 63.07 $ 35.98
Restricted Stock and Performance Share Activity	The following table reports restricted stock and performance share activity during the three years ended December 31, 2015: Weighted-Average Number of Grant Date Fair Restricted Shares Value Outstanding at December 31, 2012 751,259 $ 21.88 Granted 255,266 Performance share pay-out 41,481 Canceled (93,358 ) Vested (384,914 ) Outstanding at December 31, 2013 569,734 $ 31.86 Granted 149,349 Performance share pay-out 46,340 Canceled (43,185 ) Vested (286,249 ) Outstanding at December 31, 2014 435,989 $ 41.83 Granted 210,087 Performance share pay-out 25,228 Canceled (3,845 ) Vested (235,321 ) Outstanding at December 31, 2015 432,138 $ 56.24

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings Per Common Share	The following table sets forth the computation of basic and diluted earnings per common share: Year Ended December 31, 2015 2014 2013 (In thousands, except per share amounts) Net income from continuing operations $ 96,037 $ 74,806 $ 68,563 Net income from discontinued operations — — 7,453 Net income $ 96,037 $ 74,806 $ 76,016 Basic weighted average shares outstanding 36,690 36,930 36,886 Dilutive effect of stock options and restricted stock 947 959 1,002 Diluted weighted average shares outstanding 37,637 37,889 37,888 Basic earnings per common share Income from continuing operations $ 2.62 $ 2.03 $ 1.86 Income from discontinued operations — — 0.20 Basic earnings per share $ 2.62 $ 2.03 $ 2.06 Diluted earnings per common share Income from continuing operations $ 2.55 $ 1.97 $ 1.81 Income from discontinued operations — — 0.20 Diluted earnings per share $ 2.55 $ 1.97 $ 2.01

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments And Contingencies Disclosure [Abstract]
Summary of Minimum Rental Commitments under Operating Leases	Minimum rental commitments as of December 31, 2015 under such operating leases were as follows (in thousands): 2016 $ 3,395 2017 3,319 2018 3,042 2019 2,866 2020 2,866 2021 and thereafter 8,678 $ 24,166

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2015
Discontinued Operations And Disposal Groups [Abstract]
Summary of Greenline's Operating Results	The following is a summary of Greenline’s operating results: Year Ended December 31, 2013 (In thousands) Revenues $ 6,137 Expenses 6,384 Loss before income taxes and gain on the sale from discontinued operations (247 ) Benefit for income taxes (58 ) Gain on the sale of discontinued operations, net of tax benefit 7,642 Income from discontinued operations $ 7,453

Segment and Geographic Inform37

Segment and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Summary of Revenue and Long-lived Assets	Information regarding revenue for the three years ended December 31, 2015, 2014 and 2013 and long-lived assets as of December 31, 2015 and 2014 follows: Year Ended December 31, 2015 2014 2013 (In thousands) Revenues United States $ 262,558 $ 223,741 $ 207,519 United Kingdom 39,338 38,189 30,722 Other 1,202 844 492 Total $ 303,098 $ 262,774 $ 238,733 As of December 31, 2015 2014 (In thousands) Long-lived assets, as defined United States $ 21,968 $ 23,099 United Kingdom 8,910 9,057 Other 19 29 Total $ 30,897 $ 32,185

Organization and Principal Bu38

Organization and Principal Business Activity - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Date of incorporation	Apr. 11, 2000

Significant Accounting Polici39

Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Significant Accounting Policies [Line Items]
Maximum maturity period for classification of investments as cash equivalents	3 months
Investments other-than-temporary losses	$ 0	$ 0	$ 0
Contractual maturities accounts receivable	less than one year
Allowance for doubtful accounts	$ 109,000	3,000	100,000
Provision for bad debts	200,000	100,000	200,000
Write-offs and other charges against the allowance for doubtful accounts	$ 100,000	0	100,000
Term for post-contract technical support	1 year
Term of agreement for revenue recognition	2 years
Employee compensation and benefits	$ 83,856,000	74,995,000	64,406,000
Depreciation and amortization	18,542,000	17,379,000	$ 14,123,000
Furniture, equipment, leasehold improvements and capitalized software, net of accumulated depreciation and amortization	30,897,000	$ 32,185,000
Restatement Adjustment [Member]
Significant Accounting Policies [Line Items]
Employee compensation and benefits	2,900,000
Depreciation and amortization	1,300,000
Furniture, equipment, leasehold improvements and capitalized software, net of accumulated depreciation and amortization	$ 1,600,000
Minimum [Member]
Significant Accounting Policies [Line Items]
Estimated useful life of fixed assets	3 years
Minimum [Member] | Business Combinations [Member]
Significant Accounting Policies [Line Items]
Estimated life of intangible assets	3 years
Minimum [Member] | Internally Developed Software [Member]
Significant Accounting Policies [Line Items]
Estimated life of intangible assets	3 years
Maximum [Member]
Significant Accounting Policies [Line Items]
Estimated useful life of fixed assets	7 years
Maximum [Member] | Business Combinations [Member]
Significant Accounting Policies [Line Items]
Estimated life of intangible assets	15 years

Net Capital Requirements - Addi

Net Capital Requirements - Additional Information (Detail) $ in Millions	Dec. 31, 2015USD ($)
Brokers And Dealers [Abstract]
Aggregate net capital and financial resources in excess of required level	$ 116
Aggregate net capital and financial resources, minimum capital requirement	$ 9.4

Fair Value Measurements - Valua

Fair Value Measurements - Valuation of Company's Assets and Liabilities Measured at Fair Value (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Money market funds	$ 61,913	$ 62,126
Securities available-for-sale	84,706	64,863
Assets Fair Value Total	146,973	127,092
Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale	82,671	53,167
Municipal Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale	2,035	11,696
Foreign Exchange Contract [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Foreign currency forward position	354	103
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Money market funds	61,913	62,126
Assets Fair Value Total	61,913	62,126
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets Fair Value Total	85,060	64,966
Level 2 [Member] | Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale	82,671	53,167
Level 2 [Member] | Municipal Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale	2,035	11,696
Level 2 [Member] | Foreign Exchange Contract [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Foreign currency forward position	$ 354	$ 103

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair Value Disclosures [Abstract]
Hedge derivative expiration period	One-month period
Proceeds from the sales and maturities of securities available-for-sale	$ 35.2	$ 17.6	$ 43.4

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Foreign Currency Forward Contract (Detail) - Foreign Exchange Contract [Member] - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Derivatives Fair Value [Line Items]
Notional value	$ 45,716	$ 32,089
Fair value of notional	45,362	31,986
Fair value of the asset	354	103
Accounts Receivable [Member]
Derivatives Fair Value [Line Items]
Fair value of the asset	$ 354	$ 103

Fair Value Measurements - Sum44

Fair Value Measurements - Summary of Company's Securities Available-for-Sale (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	$ 84,972	$ 64,839
Gross unrealized gains	4	55
Gross unrealized losses	(270)	(31)
Securities available-for-sale	84,706	64,863
Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	82,937	53,146
Gross unrealized gains	4	50
Gross unrealized losses	(270)	(29)
Securities available-for-sale	82,671	53,167
Municipal Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	2,035	11,693
Gross unrealized gains		5
Gross unrealized losses		(2)
Securities available-for-sale	$ 2,035	$ 11,696

Fair Value Measurements - Sum45

Fair Value Measurements - Summary of Contractual Maturities of Securities Available-for-Sale (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Less than one year	$ 37,694	$ 36,062
Due in 1 - 5 years	47,012	28,801
Total securities available-for-sale	$ 84,706	$ 64,863

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values and Unrealized Losses on Securities Available-for-Sale (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Available For Sale Securities [Line Items]
Less than Twelve Months, Estimated fair value	$ 70,651	$ 22,626
Less than Twelve Months, Gross unrealized losses	(270)	(31)
Estimated fair value, Total	70,651	22,626
Gross unrealized losses, Total	(270)	(31)
Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Less than Twelve Months, Estimated fair value	70,651	20,487
Less than Twelve Months, Gross unrealized losses	(270)	(29)
Estimated fair value, Total	70,651	20,487
Gross unrealized losses, Total	$ (270)	(29)
Municipal Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Less than Twelve Months, Estimated fair value		2,139
Less than Twelve Months, Gross unrealized losses		(2)
Estimated fair value, Total		2,139
Gross unrealized losses, Total		$ (2)

Acquisition - Additional Inform

Acquisition - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 28, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Aggregate business acquisition purchase price				$ 37,827
Revenue		$ 303,098	$ 262,774	238,733
Net loss		$ (96,037)	$ (74,806)	(76,016)
Xtrakter Limited [Member]
Business Acquisition [Line Items]
Aggregate business acquisition purchase price	$ 37,827
Revenue				18,400
Net loss				$ 900

Acquisition - Preliminary Purch

Acquisition - Preliminary Purchase Price Allocation (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 28, 2013	Dec. 31, 2013
Business Acquisition [Line Items]
Purchase price, net of acquired cash		$ 37,827
Intangible assets	$ 13,255
Xtrakter Limited [Member]
Business Acquisition [Line Items]
Purchase price	46,683
Less: acquired cash	(8,856)
Purchase price, net of acquired cash	37,827
Accounts receivable	3,733
Intangible assets	13,255
Other assets	1,718
Deferred tax liability, net	(2,342)
Accounts payable, accrued expenses and deferred revenue	(4,622)
Goodwill	$ 26,085

Acquisition - Summary of Acquir

Acquisition - Summary of Acquired Intangible Assets (Detail) $ in Thousands	1 Months Ended
	Feb. 28, 2013USD ($)
Acquired Intangible Assets [Line Items]
Costs	$ 13,255
Customer Relationships [Member]
Acquired Intangible Assets [Line Items]
Costs	$ 5,455
Customer Relationships [Member] | Minimum [Member]
Acquired Intangible Assets [Line Items]
Estimated life of intangible assets	10 years
Customer Relationships [Member] | Maximum [Member]
Acquired Intangible Assets [Line Items]
Estimated life of intangible assets	15 years
Internally Developed Software [Member]
Acquired Intangible Assets [Line Items]
Costs	$ 5,000
Estimated life of intangible assets	3 years
Tradenames - Finite Life [Member]
Acquired Intangible Assets [Line Items]
Costs	$ 300
Estimated life of intangible assets	3 years
Non-Competition Agreements [Member]
Acquired Intangible Assets [Line Items]
Costs	$ 380
Estimated life of intangible assets	3 years
Tradename - Indefinite Life [Member]
Acquired Intangible Assets [Line Items]
Costs	$ 1,820
Other [Member]
Acquired Intangible Assets [Line Items]
Costs	$ 300

Acquisition - Pro forma Financi

Acquisition - Pro forma Financial Information (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2013USD ($)$ / shares
Business Combinations [Abstract]
Revenues	$ 242,657
Income before income taxes	107,316
Net income	$ 68,579
Basic net income per common share | $ / shares	$ 1.86
Diluted net income per common share | $ / shares	$ 1.81

Goodwill and Intangible Asset51

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Line Items]
Goodwill and intangible assets with indefinite lives	$ 64,142	$ 66,419
Amortization expense associated with identifiable intangible assets	2,300	2,300	$ 2,200
Estimated total amortization expense 2016	700
Estimated total amortization expense 2017	400
Estimated total amortization expense 2018	400
Estimated total amortization expense 2019	400
Estimated total amortization expense 2020	400
Indefinite-lived Intangible Assets [Member]
Goodwill [Line Items]
Goodwill and intangible assets with indefinite lives	$ 59,700	$ 59,700

Goodwill and Intangible Asset52

Goodwill and Intangible Assets - Summary of Company's Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Finite Lived Intangible Assets [Line Items]
Cost	$ 12,188	$ 12,202
Accumulated Amortization	(7,757)	(5,494)
Net Carrying Amount	4,431	6,707
Technology [Member]
Finite Lived Intangible Assets [Line Items]
Cost	5,770	5,770
Accumulated Amortization	(5,492)	(3,826)
Net Carrying Amount	278	1,944
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Cost	5,668	5,682
Accumulated Amortization	(1,553)	(1,183)
Net Carrying Amount	4,115	4,499
Non-Competition Agreements [Member]
Finite Lived Intangible Assets [Line Items]
Cost	380	380
Accumulated Amortization	(359)	(232)
Net Carrying Amount	21	148
Tradenames - Finite Life [Member]
Finite Lived Intangible Assets [Line Items]
Cost	370	370
Accumulated Amortization	(353)	(253)
Net Carrying Amount	$ 17	$ 117

Capitalized Software, Furnitu53

Capitalized Software, Furniture, Equipment and Leasehold Improvements - Capitalized Software Development Costs, Furniture, Equipment and Leasehold Improvements, Net of Accumulated Depreciation and Amortization (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Furniture, equipment, leasehold improvements and capitalized software, Gross	$ 100,878	$ 88,674
Accumulated depreciation and amortization	(69,981)	(56,489)
Furniture, equipment, leasehold improvements and capitalized software, net of accumulated depreciation and amortization	30,897	32,185
Software Development Costs [Member]
Property, Plant and Equipment [Line Items]
Furniture, equipment, leasehold improvements and capitalized software, Gross	60,724	50,327
Computer Hardware and Related Software [Member]
Property, Plant and Equipment [Line Items]
Furniture, equipment, leasehold improvements and capitalized software, Gross	26,328	25,513
Office Hardware [Member]
Property, Plant and Equipment [Line Items]
Furniture, equipment, leasehold improvements and capitalized software, Gross	3,414	2,785
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Furniture, equipment, leasehold improvements and capitalized software, Gross	1,955	1,921
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Furniture, equipment, leasehold improvements and capitalized software, Gross	$ 8,457	$ 8,128

Capitalized Software, Furnitu54

Capitalized Software, Furniture, Equipment and Leasehold Improvements - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Property Plant And Equipment Useful Life And Values [Abstract]
Software development costs	$ 10.6	$ 10.2

Income Taxes - Schedule of Prov

Income Taxes - Schedule of Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 38,357	$ 31,700	$ 26,071
State and local	7,180	6,505	5,958
Foreign	4,346	1,456	1,014
Total current provision	49,883	39,661	33,043
Deferred:
Federal	1,492	3,583	5,507
State and local	299	530	812
Foreign	189	(44)	(645)
Total deferred provision	1,980	4,069	5,674
Provision for income taxes	$ 51,863	$ 43,730	$ 38,717

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule Of Pre Tax Income [Line Items]
Pre-tax income from U.S. operations	$ 126,400	$ 112,500	$ 105,200
U.S. federal tax at statutory rate	35.00%	35.00%	35.00%
Stock compensation expense	$ 9,115	$ 7,266
Employee and non-employee awards	$ 56,900
Additional annual limitations	50% or greater change
Percentage of change in ownership	50.00%
Additional annual limitations period	3 years
Capital loss on the sale	$ 20,600
Capital loss carried back	1,200
Undistributed earnings of foreign subsidiaries	27,000
Undistributed earnings of foreign subsidiaries, deferred tax liability	3,300
Foreign Country [Member]
Schedule Of Pre Tax Income [Line Items]
Pre-tax income from foreign operations	21,500	$ 6,000	$ 2,100
US Country [Member]
Schedule Of Pre Tax Income [Line Items]
Net operating loss carryforwards	$ 6,700
Net operating loss carryforwards, expiration date	2,021
State [Member]
Schedule Of Pre Tax Income [Line Items]
Net operating loss carryforwards	$ 4,400
Net operating loss carryforwards, expiration date	2,017

Income Taxes - Difference Betwe

Income Taxes - Difference Between the Company's Reported Provision for Income Taxes and the U.S. Federal Statutory Rate (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
U.S. federal tax at statutory rate	35.00%	35.00%	35.00%
State and local taxes - net of federal benefit	3.40%	4.20%	4.10%
Credits and deductions related to research activities	(1.30%)	(1.70%)	(3.00%)
Foreign rate differential benefit	(2.00%)	(0.60%)	(0.30%)
Other, net			0.30%
Provision for income taxes	35.10%	36.90%	36.10%

Income Taxes - Summary of Compa

Income Taxes - Summary of Company's Net Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets
Capital loss carryforwards	$ 7,294	$ 7,428
Stock compensation expense	9,115	7,266
Other	3,745	3,482
Total deferred tax assets	22,734	21,278
Valuation allowance	(7,294)	(7,428)	$ (7,743)	$ (727)
Net deferred tax assets	15,440	13,850
Deferred tax liabilities
Depreciation and amortization	(1,953)	(2,461)
Capitalized software development costs	(4,344)	(4,495)
Intangible assets	(1,310)	(1,854)
Deferred tax assets, net	7,833	5,040
US Country [Member]
Deferred tax assets
U.S. net operating loss carryforwards	$ 2,580	$ 3,102

Income Taxes - Summary of Chang

Income Taxes - Summary of Changes in Valuation Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Valuation allowance at beginning of year	$ 7,428	$ 7,743	$ 727
Current year income		(101)	(65)
State net operating loss		(155)	(406)
Blended state rate changes	(71)
Capital (loss) gain	(63)	(59)	7,487
Valuation allowance at end of year	$ 7,294	$ 7,428	$ 7,743

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of the Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 265	$ 265	$ 49
Additions for tax positions of current year	0	0	235
Reductions for tax positions of prior years	0	0	(19)
Balance at end of year	$ 265	$ 265	$ 265

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jul. 31, 2014	Jan. 31, 2014
Class of Stock [Line Items]
Common stock, shares authorized		110,000,000	110,000,000
Common stock entitles		One
Shares repurchase program authorized					$ 65,000,000	$ 35,000,000
Shares repurchase program expiration date		Feb. 29, 2016
Cash dividends declared per common share		$ 0.80	$ 0.64	$ 0.52
Quarterly dividends payable, date to be paid		Feb. 25, 2016
Quarterly dividends payable, date of record		Feb. 11, 2016
Subsequent Event [Member]
Class of Stock [Line Items]
Shares repurchase program authorized	$ 25,000,000
Cash dividends declared per common share	$ 0.26
Common Stock Non-Voting [Member]
Class of Stock [Line Items]
Common stock, shares authorized		10,000,000	10,000,000
Common Stock Voting [Member]
Class of Stock [Line Items]
Common stock, shares authorized		110,000,000

Stockholders' Equity - Summary

Stockholders' Equity - Summary of the Companys Change in the Common Stock (Detail) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Class of Stock [Line Items]
Outstanding shares of voting common stock at the beginning of year	37,318,722
Exercise of stock options	196,034	165,340	256,622
Outstanding shares of voting common stock at the end of year	37,409,274	37,318,722
Voting Common Stock [Member]
Class of Stock [Line Items]
Outstanding shares of voting common stock at the beginning of year	37,319,000	37,729,000	37,407,000
Exercise of stock options	183,000	120,000	256,000
Issuance of restricted stock, net of shares withheld for tax payments and cancellations	178,000	116,000	66,000
Repurchases	(271,000)	(646,000)
Outstanding shares of voting common stock at the end of year	37,409,000	37,319,000	37,729,000

Stock-Based Compensation Plan63

Stock-Based Compensation Plans - Additional Information (Detail) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2015USD ($)Incentive$ / sharesshares	Dec. 31, 2014$ / shares	Dec. 31, 2013$ / shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of stock incentive plans | Incentive		2
Shares available for grant under the stock incentive plans | shares		612,857
Exercise price for the shares of the Company's common stock | $ / shares		$ 36.46	$ 19.25	$ 19.61
Grant date fair value | $		$ 15,312
Fair value assumptions, Dividend yield rate		1.10%	1.00%	1.20%
Closing price of common stock | $ / shares		$ 111.59
Unrecognized compensation costs related to non-vested | $		$ 1,500
Weighted-average period over which cost is expected to be recognized		3 years 3 months 18 days
Pay-out ranges, Minimum		0.00%
Pay-out ranges, Maximum		150.00%
Pay-out achievement		130.00%	85.00%	108.00%
Restricted Stock and Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs related to non-vested | $		$ 16,500
Weighted-average period over which cost is expected to be recognized		1 year 10 months 24 days
Employees Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period vested for option grants		1 year
Number of non-option equity instruments granted during the period | shares		0
Percentage of shares grant to participants		20.00%
Total stock-based compensation | $		$ 26
Chief Executive Officer [Member] | Minimum Performance Level [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, equity instruments other than options, nonvested, number | shares	35,463
Chief Executive Officer [Member] | Above the Minimum Performance Level [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, equity instruments other than options, nonvested, number | shares	92,419
Chief Executive Officer [Member] | Incentive Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options Expiration Period		5 years 6 months
Exercise price for the shares of the Company's common stock | $ / shares	$ 88.25
Number of stock option equity instruments granted during the period | shares	119,981
Grant date fair value | $	$ 2,000
Percentage of fair market value of the common stock on the grant date	125.00%
Fair value assumptions, Risk free interest rate	1.40%
Fair value assumptions, Volatility rate	27.30%
Fair value assumptions, Dividend yield rate	0.90%
Chief Executive Officer [Member] | Performance Based Share [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant date fair value | $	$ 6,000
Fair value assumptions, Risk free interest rate	1.30%
Fair value assumptions, Volatility rate	27.30%
Fair value assumptions, Dividend yield rate	0.90%
Number of non-option equity instruments granted during the period | shares	116,659
Chief Executive Officer [Member] | January 15, 2019 [Member] | Above the Minimum Performance Level [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting rights	50.00%
Chief Executive Officer [Member] | January 15, 2020 [Member] | Minimum Performance Level [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting rights	100.00%
Chief Executive Officer [Member] | January 15, 2020 [Member] | Above the Minimum Performance Level [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting rights	50.00%
Chief Executive Officer [Member] | Share-based Compensation Award, Tranche One [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award award vesting date		Jan. 15, 2018
Chief Executive Officer [Member] | Share-based Compensation Award, Tranche One [Member] | January 15, 2018 [Member] | Incentive Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting rights		33.33%
Chief Executive Officer [Member] | Share-based Compensation Award, Tranche One [Member] | January 15, 2019 [Member] | Above the Minimum Performance Level [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting rights	50.00%
Chief Executive Officer [Member] | Share-based Compensation Award, Tranche Two [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award award vesting date		Jan. 15, 2019
Chief Executive Officer [Member] | Share-based Compensation Award, Tranche Two [Member] | January 15, 2019 [Member] | Incentive Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting rights		33.33%
Chief Executive Officer [Member] | Share-based Compensation Award, Tranche Two [Member] | January 15, 2020 [Member] | Above the Minimum Performance Level [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting rights	50.00%
Chief Executive Officer [Member] | Share-based Compensation Award, Tranche Three [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award award vesting date		Jan. 15, 2020
Chief Executive Officer [Member] | Share-based Compensation Award, Tranche Three [Member] | January 15, 2020 [Member] | Incentive Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting rights		33.33%
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period vested for option grants		3 years
Options Expiration Period		7 years
Minimum [Member] | Restricted Stock and Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period vested for option grants		3 years
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period vested for option grants		5 years
Options Expiration Period		10 years
Maximum [Member] | Restricted Stock and Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period vested for option grants		5 years

Stock-Based Compensation Plan64

Stock-Based Compensation Plans - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	$ 11,618	$ 8,869	$ 8,169
Employees [Member] | Restricted Stock and Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	10,792	8,193	7,269
Employees [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	826	676	900
Non-Employee Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	12,519	9,769	8,879
Non-Employee Directors [Member] | Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	$ 901	$ 900	$ 710

Stock-Based Compensation Plan65

Stock-Based Compensation Plans - Assumptions Used for the Black-Scholes Option-Pricing Model to Determine the Per Share Weighted Average Fair Value for Options Granted (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Expected life (years)	7 years	5 years	9 years 10 months 24 days
Risk-free interest rate	1.90%	1.70%	1.90%
Expected volatility	56.70%	35.50%	44.30%
Expected dividend yield	1.10%	1.00%	1.20%

Stock-Based Compensation Plan66

Stock-Based Compensation Plans - Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Beginning balance	1,014,420	1,220,449	1,429,822
Number of Shares, Granted	120,650	382	51,597
Number of Shares, Canceled		(41,071)	(4,348)
Number of Shares, Exercised	(196,034)	(165,340)	(256,622)
Number of Shares, Ending Balance	939,036	1,014,420	1,220,449
Number of Shares, Exercisable	790,471
Weighted Average Exercise Price, Beginning Balance	$ 13.81	$ 15.01	$ 13.62
Weighted Average Exercise Price, Granted	88.15	63.07	41.75
Weighted Average Exercise Price, Canceled		41.47	33.84
Weighted Average Exercise Price, Exercised	11.60	15.85	12.33
Weighted Average Exercise Price, Ending Balance	23.83	$ 13.81	$ 15.01
Weighted Average Exercise Price, Exercisable	$ 14.07
Remaining contractual term, Outstanding at December 31, 2013	2 years 10 months 24 days
Remaining contractual term, Exercisable at December 31, 2014	2 years 7 months 6 days
Intrinsic Value, Exercised	$ 15,312
Intrinsic Value, Ending Balance	82,412
Intrinsic Value, Exercisable	$ 77,084

Stock-Based Compensation Plan67

Stock-Based Compensation Plans - Summary of Performance of Share Activity (Detail) - Performance Shares [Member] - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share pay-out at plan	28,520	29,678	42,908
Actual share pay-out in following year	37,076	25,228	46,340
Weighted average fair value per share on grant date	$ 70.60	$ 63.07	$ 35.98

Stock-Based Compensation Plan68

Stock-Based Compensation Plans - Restricted Stock and Performance Share Activity (Detail) - Restricted Stock [Member] - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Restricted Shares, Beginning balance	435,989	569,734	751,259
Number of Restricted Shares, Granted	210,087	149,349	255,266
Number of Restricted Shares, Performance share pay-out	25,228	46,340	41,481
Number of Restricted Shares, Canceled	(3,845)	(43,185)	(93,358)
Number of Restricted Shares, Vested	(235,321)	(286,249)	(384,914)
Number of Restricted Shares, Ending balance	432,138	435,989	569,734
Weighted Average Grant Date Fair Value, Beginning balance	$ 41.83	$ 31.86	$ 21.88
Weighted Average Grant Date Fair Value, Ending balance	$ 56.24	$ 41.83	$ 31.86

Earnings Per Share - Computatio

Earnings Per Share - Computation of Basic and Diluted Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share Basic And Diluted [Abstract]
Net income from continuing operations	$ 96,037	$ 74,806	$ 68,563
Net income from discontinued operations			7,453
Net income	$ 96,037	$ 74,806	$ 76,016
Basic weighted average shares outstanding	36,690	36,930	36,886
Dilutive effect of stock options and restricted stock	947	959	1,002
Diluted weighted average shares outstanding	37,637	37,889	37,888
Income from continuing operations	$ 2.62	$ 2.03	$ 1.86
Income from discontinued operations			0.20
Net income per common share	2.62	2.03	2.06
Income from continuing operations	2.55	1.97	1.81
Income from discontinued operations			0.20
Net income per common share	$ 2.55	$ 1.97	$ 2.01

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Detail) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock Options and Restricted Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Stock options and restricted stock excluded from the computation of diluted earnings per share	128,383	66,637	160,838

Credit Agreement - Additional I

Credit Agreement - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2013	Dec. 31, 2015	Oct. 31, 2015
Line Of Credit Facility [Line Items]
Revolving loans and letters of credit	$ 50,000,000		$ 100,000,000
Letter of credit outstanding		$ 1,100,000
Additional Credit Agreement	$ 50,000,000
Amount available under credit agreement		$ 98,900,000
Period of credit agreement	3 years
LIBOR rate description		the federal funds effective rate plus 0.50% and (c) one month adjusted LIBOR plus 1.00% plus (ii) 0.50% or (B) the sum of (i) adjusted LIBOR plus (ii) 1.50%
Federal funds effective rate		0.50%
One month adjusted LIBOR		1.00%
LIBOR Rate		0.50%
Adjusted LIBOR rate		1.50%
Interest per annum		2.00%
Revolving loan commitment rate		0.40%
Equity interest		65.00%
Maximum [Member]
Line Of Credit Facility [Line Items]
Total leverage ratio		250.00%
Minimum [Member]
Line Of Credit Facility [Line Items]
Interest coverage ratio		350.00%
Adjusted EBITDA		$ 80,000,000
Excess judgments against the company		$ 10,000,000
Standby Letters of Credit [Member]
Line Of Credit Facility [Line Items]
Revolving loans and letters of credit			$ 5,000,000
Credit Agreement [Member]
Line Of Credit Facility [Line Items]
Expiration period of credit agreement		Oct. 31, 2017

Commitments and Contingencies -

Commitments and Contingencies - Summary of Minimum Rental Commitments under Operating Leases (Detail) $ in Thousands	Dec. 31, 2015USD ($)
Operating Leases Future Minimum Payments Due [Abstract]
2,016	$ 3,395
2,017	3,319
2,018	3,042
2,019	2,866
2,020	2,866
2021 and thereafter	8,678
Operating Leases	$ 24,166

Commitments and Contingencies73

Commitments and Contingencies - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)AgreementSubsidiary	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Loss Contingencies [Line Items]
Rental expense	$ 4.1	$ 3.8	$ 3.8
Number of lease agreements assigned to third parties | Agreement	1
Lease termination dates	2020-11
Future lease obligation under sublease arrangement	$ 1.4
Number of subsidiaries | Subsidiary	2
Settlement days of bond transaction	Within one to three trading days
Revenues from riskless principal trading	$ 16.9	7.4	6
Collateral deposits	1.5
General and Administrative Expense [Member]
Loss Contingencies [Line Items]
Clearing expenses	3.3	$ 1.3	$ 0.9
Standby Letters of Credit [Member]
Loss Contingencies [Line Items]
Contingent obligation for standby letter of credit issued to Landlord	$ 1.1

Discontinued Operations - Addit

Discontinued Operations - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2013	Dec. 31, 2013
Discontinued Operation Income Loss From Discontinued Operation Disclosures [Abstract]
Recognized gain, net of tax	$ 7,600	$ 7,642
Stock purchase agreement	100.00%
Aggregate purchase price	$ 11,000

Discontinued Operations - Summa

Discontinued Operations - Summary of Greenline's Operating Results (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2013	Dec. 31, 2013
Discontinued Operation Income Loss From Discontinued Operation Disclosures [Abstract]
Revenues		$ 6,137
Expenses		6,384
Loss before income taxes and gain on the sale from discontinued operations		(247)
Benefit for income taxes		(58)
Gain on the sale of discontinued operations, net of tax benefit	$ 7,600	7,642
Income from discontinued operations		$ 7,453

Segment and Geographic Inform76

Segment and Geographic Information - Additional Information (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Geographic Concentration Risk [Member] | Total Revenue and Long-lived Assets [Member] | United Kingdom [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Concentration Risk, Percentage	10.00%	10.00%	10.00%

Segment and Geographic Inform77

Segment and Geographic Information - Summary of Revenue and Long-lived Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Revenues	$ 303,098	$ 262,774	$ 238,733
Long-lived assets	30,897	32,185
United States [Member]
Segment Reporting Information [Line Items]
Revenues	262,558	223,741	207,519
Long-lived assets	21,968	23,099
United Kingdom [Member]
Segment Reporting Information [Line Items]
Revenues	39,338	38,189	30,722
Long-lived assets	8,910	9,057
Other [Member]
Segment Reporting Information [Line Items]
Revenues	1,202	844	$ 492
Long-lived assets	$ 19	$ 29

Deferred Compensation Plans - A

Deferred Compensation Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Compensation And Retirement Disclosure [Abstract]
Contribution to defined plans	$ 1.9	$ 1.8	$ 1.7
Non-qualified deferred cash incentive plan maximum eligibility percentage of employees	100.00%

Customer Concentration - Additi

Customer Concentration - Additional Information (Detail) - Customer	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Concentration Risk [Line Items]
Number of client accounted for total revenue	0	0	0
Percentage of outstanding shares owned by single client	8.90%
Customer Concentration Risk | Trading Volume
Concentration Risk [Line Items]
Percentage of trading volumes by single client	15.30%	14.00%	12.50%