Greenhill & Co (GHL) 10-Q 8 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 31, 2018
Document Documentand Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Trading Symbol	GHL
Entity Registrant Name	GREENHILL & CO INC
Entity Central Index Key	1,282,977
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		22,565,511

Condensed Consolidated Statemen

Condensed Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents ($3.8 million and $3.9 million restricted from use at June 30, 2018 and December 31, 2017, respectively)	$ 149,286	$ 267,646
Advisory fees receivable, net of allowance for doubtful accounts of $0.0 million and $0.3 million at June 30, 2018 and December 31, 2017, respectively	98,899	64,244
Other receivables	4,400	3,964
Property and equipment, net of accumulated depreciation of $43.9 million and $62.1 million at June 30, 2018 and December 31, 2017, respectively	8,116	8,602
Goodwill	211,417	217,737
Deferred tax asset, net	40,183	42,345
Other assets	12,483	6,279
Total assets	524,784	610,817
Liabilities and Equity
Compensation payable	40,203	26,022
Accounts payable and accrued expenses	21,951	15,443
Current income taxes payable	7,851	5,311
Secured term loan payable	331,451	339,048
Contingent obligation due selling unitholders of Cogent	17,354	13,763
Deferred tax liability	3,409	2,928
Total liabilities	422,219	402,515
Common stock, par value $0.01 per share; 100,000,000 shares authorized, 44,823,361 and 43,750,170 shares issued as of June 30, 2018 and December 31, 2017, respectively; 22,873,749 and 27,084,520 shares outstanding as of June 30, 2018 and December 31, 2017, respectively	448	438
Restricted stock units	55,843	80,512
Additional paid-in capital	840,249	800,806
Exchangeable shares of subsidiary; 257,156 shares issued as of both June 30, 2018 and December 31, 2017; 32,804 shares outstanding as of both June 30, 2018 and December 31, 2017	1,958	1,958
Retained earnings	43,714	37,595
Accumulated other comprehensive income (loss)	(29,461)	(22,222)
Treasury stock, at cost, par value $0.01 per share; 21,949,612 and 16,665,650 shares as of June 30, 2018 and December 31, 2017, respectively	(810,186)	(690,785)
Stockholders’ equity	102,565	208,302
Total liabilities and equity	$ 524,784	$ 610,817

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Cash and cash equivalents, restricted from use	$ 3.8	$ 3.9
Advisory fees receivable, allowance for doubtful accounts	0	0.3
Property and equipment, accumulated depreciation	$ 43.9	$ 62.1
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (shares)	100,000,000	100,000,000
Common stock, shares issued (shares)	44,823,361	43,750,170
Common stock, shares outstanding (shares)	22,873,749	27,084,520
Exchangeable shares of subsidiary, shares issued (shares)	257,156	257,156
Exchangeable shares of subsidiary, shares outstanding (shares)	32,804	32,804
Treasury stock, par value (usd per share)	$ 0.01	$ 0.01
Treasury stock, shares (shares)	21,949,612	16,665,560

Condensed Consolidated Stateme4

Condensed Consolidated Statements of Operations (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues
Advisory revenues	$ 88,051	$ 67,038	$ 174,820	$ 123,738
Investment revenues	445	231	1,219	460
Total revenues	88,496	67,269	176,039	124,198
Expenses
Employee compensation and benefits	48,438	38,843	97,646	82,893
Occupancy and equipment rental	5,508	5,290	10,797	9,998
Depreciation and amortization	717	760	1,480	1,546
Information services	2,652	2,222	4,969	4,634
Professional fees	2,247	2,001	5,170	3,611
Travel related expenses	3,492	3,494	6,797	6,214
Other operating expenses	5,986	4,294	10,708	1,944
Total operating expenses	69,040	56,904	137,567	110,840
Total operating income	19,456	10,365	38,472	13,358
Interest expense	5,594	789	10,855	1,608
Income before taxes	13,862	9,576	27,617	11,750
Provision for taxes	3,349	3,331	10,736	6,251
Net income	$ 10,513	$ 6,245	$ 16,881	$ 5,499
Average shares outstanding:
Basic (shares)	26,992,652	31,933,830	28,545,545	32,151,409
Diluted (shares)	27,921,821	31,977,479	29,224,878	32,251,500
Earnings per share:
Basic (usd per share)	$ 0.39	$ 0.20	$ 0.59	$ 0.17
Diluted (usd per share)	0.38	0.20	0.58	0.17
Dividends declared and paid per share (usd per share)	$ 0.05	$ 0.45	$ 0.10	$ 0.9

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 10,513	$ 6,245	$ 16,881	$ 5,499
Currency translation adjustment, net of tax	(6,405)	2,115	(7,239)	6,731
Comprehensive income	$ 4,108	$ 8,360	$ 9,642	$ 12,230

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Restricted Stock UnitsRestricted Stock Units	Additional Paid-in Capital	Exchangeable Shares of Subsidiary	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of the change in accounting principle related to revenue recognition						$ 0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance						111,798
Beginning Balance at Dec. 31, 2016		$ 414	$ 85,907	$ 734,728	$ 1,958	111,798	$ (32,398)	$ (611,224)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued		24		65,231
Restricted stock units recognized, net of forfeitures			40,597
Restricted stock units delivered			(45,992)
Tax benefit from the delivery of restricted stock units				847
Exchangeable shares of subsidiary delivered					0
Dividends						(47,552)
Net income (loss)						(26,651)
Currency translation adjustment, net of tax							10,176
Repurchased								(79,561)
Ending Balance at Dec. 31, 2017	$ 208,302	438	80,512	800,806	1,958	37,595	(22,222)	(690,785)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of the change in accounting principle related to revenue recognition						(7,645)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance						29,950
Stock issued		10		39,443
Restricted stock units recognized, net of forfeitures			15,243
Restricted stock units delivered			(39,912)
Tax benefit from the delivery of restricted stock units				0
Exchangeable shares of subsidiary delivered					0
Dividends						(3,117)
Net income (loss)	16,881					16,881
Currency translation adjustment, net of tax	(7,239)						(7,239)
Repurchased								(119,401)
Ending Balance at Jun. 30, 2018	$ 102,565	$ 448	$ 55,843	$ 840,249	$ 1,958	$ 43,714	$ (29,461)	$ (810,186)

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Treasury stock, par value (usd per share)	0.01	0.01
Common Stock
Common stock, par value (usd per share)	0.01	0.01
Treasury Stock
Treasury stock, par value (usd per share)	$ 0.01	$ 0.01

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating activities:
Net income (loss)	$ 16,881	$ 5,499
Non-cash items included in net income:
Depreciation and amortization	2,632	1,546
Net investment (gains) losses	149	25
Restricted stock units recognized, net	15,243	20,263
Deferred taxes, net	6,069	3,895
Loss (gain) on fair value of contingent obligation	3,591	(7,513)
Loss (gain) on sales of property and equipment	(777)	0
Changes in operating assets and liabilities:
Advisory fees receivable	(34,655)	18,020
Other receivables and assets	(6,789)	(580)
Compensation payable	14,181	(14,827)
Accounts payable and accrued expenses	(4,292)	(926)
Current income taxes payable	2,540	(13,332)
Net cash provided by operating activities	14,773	12,070
Investing activities:
Distributions from investments	2	60
Purchases of property and equipment	(1,623)	(1,187)
Sales of property and equipment	1,357	0
Net cash used in investing activities	(264)	(1,127)
Financing activities:
Proceeds from revolving bank loan	0	42,430
Repayment of revolving bank loan	0	(37,850)
Repayment of bank term loans	0	(5,625)
Repayment of secured term loan	(8,750)	0
Dividends paid	(3,117)	(30,794)
Purchase of treasury stock	(119,401)	(12,733)
Net cash used in financing activities	(131,268)	(44,572)
Effect of exchange rate changes	(1,601)	3,338
Net decrease in cash and cash equivalents	(118,360)	(30,291)
Cash and cash equivalents, beginning of the period	267,646	98,313
Cash and cash equivalents, end of the period	149,286	68,022
Supplemental disclosure of cash flow information:
Cash paid for interest	11,309	1,827
Cash paid for taxes, net of refunds	$ 2,998	$ 16,225

Organization

Organization	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Greenhill & Co., Inc. and subsidiaries (the "Company" or "Greenhill") is a leading independent investment bank that provides financial and strategic advice on significant domestic and cross-border mergers and acquisitions, restructurings, financings, capital raisings and other strategic transactions to a diverse client base, including corporations, partnerships, institutions and governments globally. We act for clients located throughout the world from our global offices in the United States, Australia, Brazil, Canada, Germany, Hong Kong, Japan, Spain, Sweden, and the United Kingdom. The Company's wholly-owned subsidiaries provide advisory services in various jurisdictions. Our most significant operating entities include: Greenhill & Co., LLC (“G&Co”), Greenhill & Co. International LLP (“GCI”), Greenhill & Co. Europe LLP (“GCE”), Greenhill & Co. Australia Pty Limited (“Greenhill Australia”) and Greenhill Cogent, LP (“GC LP”). G&Co is engaged in investment banking activities principally in the United States. G&Co is registered as a broker-dealer with the Securities and Exchange Commission (“SEC”) and the Financial Industry Regulatory Authority (“FINRA”), and is licensed in all 50 states and the District of Columbia. GCI and GCE are engaged in investment banking activities in the United Kingdom and Europe, respectively, and are subject to regulation by the U.K. Financial Conduct Authority (“FCA”). Greenhill Australia engages in investment banking activities in Australia and New Zealand and is licensed and subject to regulation by the Australian Securities and Investment Commission (“ASIC”). GC LP is engaged in capital advisory services to institutional investors principally in the United States and is registered as a broker-dealer with the SEC and FINRA. The Company also operates in other locations throughout the world which are subject to regulation by other governmental and regulatory bodies and self-regulatory authorities.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Financial Information These condensed consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States (U.S. GAAP), which require management to make estimates and assumptions regarding future events that affect the amounts reported in our financial statements and these footnotes, including investment valuations, compensation accruals, income tax expense related to the Tax Cuts and Jobs Act, and other matters. Management believes that the estimates used in preparing its condensed consolidated financial statements are reasonable and prudent. Actual results could differ materially from those estimates. Certain reclassifications have been made to prior year information to conform to current year presentation. The condensed consolidated financial statements of the Company include all consolidated accounts of Greenhill & Co., Inc. and all other entities in which the Company has a controlling interest after eliminations of all significant inter-company accounts and transactions. These condensed consolidated financial statements are unaudited and should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2017 included in the Company's Annual Report on Form 10-K filed with the SEC. The condensed consolidated financial information as of December 31, 2017 has been derived from audited consolidated financial statements not included herein. The results of operations for interim periods are not necessarily indicative of results for the entire year. Revenue Recognition Advisory Revenues The Company adopted ASU 2014-09, Revenue from Contracts with Customers, on January 1, 2018. The Company’s accounting policies for advisory revenues following the adoption of this ASU are included below. The Company's accounting policies for advisory revenues prior to adopting ASU 2014-09 are included in “Note 2 — Summary of Significant Accounting Policies” in the Company's 2017 Annual Report on Form 10-K filed with the SEC. The Company recognizes revenue when (or as) services are transferred to clients. Revenue is recognized based on the amount of consideration that management expects to receive in exchange for these services in accordance with the terms of the contract with the client. To determine the amount and timing of revenue recognition, the Company must (1) identify the contract with the client, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when (or as) the Company satisfies a performance obligation. The Company generally recognizes advisory fee revenues for mergers and acquisitions engagements at the earlier of the announcement date or transaction date, as the performance obligation is typically satisfied at such time. Upfront fees and certain retainer fees are generally deferred until the announcement or transaction date as they are considered constrained (subject to significant reversal) prior to the announcement or transaction date. Fairness opinion fees are recognized when the opinion is delivered. The Company recognizes advisory fee revenues for financing advisory and restructuring engagements as the services are provided to the client, based on terms of the engagement letter. In such arrangements, the Company’s performance obligations are to provide financial and strategic advice throughout an engagement. The Company recognizes revenues for capital advisory fees when (1) the commitment of capital is secured (primary capital raising transactions) or the sale or transfer of the capital interest occurs (secondary market transactions) and (2) the fees are earned from the client in accordance with terms of the engagement letter. Upfront fees and certain retainer fees are deferred until the commitment is secured or the sale or transfer of the capital interest occurs, as the fees are considered constrained (subject to significant reversal) prior to such time. As a result of the deferral of certain fees, including the cumulative effect adjustment of $10.2 million recorded upon adoption of ASU 2014-09, deferred revenue (also known as contract liabilities) was $10.4 million and $12.3 million as of June 30, 2018 and January 1, 2018, respectively. Deferred revenue is included in accounts payable and accrued expenses in the condensed consolidated statements of financial condition. During the six months ended June 30, 2018 , the Company recognized $8.1 million of advisory fee revenues that were included in the deferred revenue (contract liabilities) balance at adoption. The Company’s clients reimburse certain expenses incurred by the Company in the conduct of advisory engagements. Client reimbursements totaled $2.2 million and $1.0 million for the three months ended June 30, 2018 and 2017 , respectively, and $3.4 million and $2.1 million for the six months ended June 30, 2018 and 2017 . Such reimbursements were reported as advisory revenues and operating expenses for the three and six months ended June 30, 2018 and as a reduction to operating expenses for the three and six months ended June 30, 2017 , with no impact to operating income in the periods presented. Investment Revenues Investment revenues consist of gains (or losses) on the Company's investments in certain merchant banking funds and interest income. The Company recognizes revenue on its investments in merchant banking funds based on its allocable share of realized and unrealized gains (or losses) reported by such funds. The Company’s revenue recognition for investment revenues, which represent less than 1% of total revenues, was not impacted by the adoption of ASU 2014-09. Cash and Cash Equivalents The Company’s cash and cash equivalents consist of (i) cash held on deposit with financial institutions, (ii) cash equivalents and (iii) restricted cash. The Company maintains its cash and cash equivalents with financial institutions with high credit ratings. The Company considers all highly liquid investments with a maturity date of three months or less, when purchased, to be cash equivalents. Cash equivalents primarily consist of money market funds, commercial paper, Treasury bills and short-term government bonds and are carried at cost plus accrued interest, which approximates the fair value due to the short-term nature of these investments. Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. See "Note 3 — Cash and Cash Equivalents". Advisory Fees Receivable Receivables are stated net of an allowance for doubtful accounts. The estimate for the allowance for doubtful accounts is derived by the Company by utilizing past client transaction history and an assessment of the client’s creditworthiness. The Company recorded a bad debt expense of $0.3 million for the three and six month periods ended June 30, 2018 and a bad debt expense of $0.8 million for the three and six month periods ended June 30, 2017 . Included in the advisory fees receivable balance at June 30, 2018 and December 31, 2017 were $25.4 million and $29.3 million , respectively, of long term receivables related to primary capital advisory engagements which are generally paid in installments over a period of three years . Included as a component of investment revenues is interest income related to primary capital advisory engagements of $0.2 million for the each of the three months ended June 30, 2018 and 2017 , and $0.4 million for each of the six months ended June 30, 2018 and 2017 . Credit risk related to advisory fees receivable is disbursed across a large number of clients located in various geographic areas. The Company controls credit risk through credit approvals and monitoring procedures but does not require collateral to support accounts receivable. Goodwill Goodwill is the cost in excess of the fair value of identifiable net assets at the acquisition date. The Company tests its goodwill for impairment at least annually. An impairment loss is triggered if the estimated fair value of an operating unit is less than the estimated net book value. Such loss is calculated as the difference between the estimated fair value of goodwill and its carrying value. Goodwill is translated at the rate of exchange prevailing at the end of the periods presented in accordance with the accounting guidance for foreign currency translation. Any translation gain or loss is included in the foreign currency translation adjustment, which is included as a component of other comprehensive income (loss) in the condensed consolidated statements of changes in stockholders' equity. Other Assets Included in other assets in the condensed consolidated statements of financial condition are the Company's investments in merchant banking funds, which are recorded under the equity method of accounting based upon the Company's proportionate share of the estimated fair value of the underlying merchant banking fund's net assets. Other assets also include prepaid compensation awards that require a future service period and are subject to clawbacks if the individual ceases employment prior to a determined date. The awards are amortized over the required service period, which generally does not exceed one year. Other prepaid expenses, rent deposits, intangible assets and other tangible assets are also included in other assets. Compensation Payable Included in compensation payable are discretionary compensation awards comprised of accrued cash bonuses and long-term incentive compensation, consisting of deferred cash retention awards, which are non-interest bearing, and generally amortized over a three to five year service period after the date of grant. Restricted Stock Units The Company accounts for its share-based compensation payments by recording the fair value of restricted stock units granted to employees as compensation expense. The restricted stock units are generally amortized over a four to five -year service period following the date of grant. Compensation expense is determined based upon the fair value of the Company’s common stock at the date of grant. In certain circumstances the Company issues share-based compensation, which is contingent on achievement of certain performance targets. Compensation expense for performance-based awards begins at the time it is deemed probable that the performance target will be achieved and is amortized into expense over the remaining service period. As the Company expenses the awards, the restricted stock units recognized are recorded within stockholders' equity. The restricted stock units are reclassified into common stock and additional paid-in capital upon vesting. The Company records as treasury stock the repurchase of stock delivered to its employees in settlement of tax liabilities incurred upon the vesting of restricted stock units. The Company records dividend equivalent payments on outstanding restricted stock units eligible for such payment as a dividend payment and a charge to stockholders' equity. Earnings per Share The Company calculates basic earnings per share (“EPS”) by dividing net income by the sum of (i) the weighted average number of shares outstanding for the period and (ii) the weighted average number of shares deemed issuable due to the vesting of restricted stock units for accounting purposes. See "Note 7 — Equity". The Company calculates diluted EPS by dividing net income by the sum of (i) basic shares per above and (ii) the dilutive effect of the common stock deliverable pursuant to restricted stock units for which future service is required. Under the treasury method, the number of shares issuable upon the vesting of restricted stock units included in the calculation of diluted EPS is the excess, if any, of the number of shares expected to be issued, less the number of shares that could be repurchased by the Company with the proceeds to be received upon settlement at the average market closing price during the reporting period. See "Note 8 — Earnings per Share". Provision for Taxes The Company accounts for taxes in accordance with the accounting guidance for income taxes which requires the recognition of tax benefits or expenses on the temporary differences between the financial reporting and tax bases of its assets and liabilities. The Company follows the guidance for income taxes in recognizing, measuring, presenting and disclosing in its financial statements uncertain tax positions taken or expected to be taken on its income tax returns. Income tax expense is based on pre-tax accounting income, including adjustments made for the recognition or derecognition related to uncertain tax positions. The recognition or derecognition of income tax expense related to uncertain tax positions is determined under the guidance, and the Company's policy is to treat interest and penalties related to uncertain tax positions as part of pre-tax income. Deferred tax assets and liabilities are recognized for the future tax attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in earnings in the period of change. Management applies the “more-likely-than-not criteria” when determining tax benefits. Foreign Currency Translation Assets and liabilities denominated in foreign currencies have been translated at rates of exchange prevailing at the end of the periods presented in accordance with the accounting guidance for foreign currency translation. Income and expenses transacted in foreign currency have been translated at average monthly exchange rates during the period. Translation gains and losses are included in the foreign currency translation adjustment, which is included as a component of other comprehensive income (loss) in the condensed consolidated statements of changes in stockholders' equity. Foreign currency transaction gains and losses are included in the condensed consolidated statements of operations in other operating expenses. Financial Instruments and Fair Value The Company accounts for financial instruments measured at fair value in accordance with accounting guidance for fair value measurements and disclosures which establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy under the pronouncement are described below: Basis of Fair Value Measurement Level 1 – Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; Level 2 – Quoted prices in markets that are not active or financial instruments for which all significant inputs are observable, either directly or indirectly; and Level 3 – Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. In determining the appropriate levels, the Company performs an analysis of the assets and liabilities that are subject to these disclosures. At each reporting period, all assets and liabilities for which the fair value measurement is based on significant unobservable inputs or instruments which trade infrequently and therefore have little or no price transparency are classified as Level 3. Transfers between levels are recognized as of the end of the period in which they occur. See "Note 4 — Fair Value of Financial Instruments". Property and Equipment Property and equipment is stated at cost less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the life of the assets. Amortization of leasehold improvements is computed using the straight-line method over the lesser of the life of the asset or the remaining term of the lease. Estimated useful lives of the Company’s fixed assets are generally as follows: Aircraft – 7 years Equipment – 5 years Furniture and fixtures – 7 years Leasehold improvements – the lesser of 10 years or the remaining lease term Business Information The Company's activities as an investment banking firm constitute a single business segment, with substantially all revenues generated from advisory services, which includes engagements relating to mergers and acquisitions, financing advisory and restructuring, and capital advisory services. The Company earns less than 1% of its revenues from interest income and investment gains (losses) on investments. Recently Adopted Accounting Pronouncements In May 2014, the FASB issued ASU 2014-09 "Revenue from Contracts with Customers" codifying ASC 606, Revenue Recognition - Revenue from Contracts with Customers, which supersedes the guidance in former ASC 605, Revenue Recognition. The Company adopted this standard on January 1, 2018 utilizing the modified retrospective approach and applied the standard to contracts that were not completed at this time. Upon adoption, certain revenues that were previously recognized as services were provided changed to either point in time recognition or over the term of an engagement. This change in the Company's revenue recognition policy created deferred revenues (also known as contract liabilities) that will be recognized at a point in time as performance obligations are met. The cumulative effect of adopting this ASU on January 1, 2018 was a net decrease to retained earnings of $7.6 million . The Company also changed the presentation of certain reimbursed costs from a net presentation prior to adoption to a gross presentation following adoption. Accounting Developments In February 2016, the FASB issued ASU No. 2016-02, Leases ("ASU 2016-02"). ASU 2016-02 requires the recognition of lease assets and lease liabilities for operating leases, among other changes. This ASU also requires expanded disclosures about the nature and terms of leases. Management is currently evaluating the impact of the future adoption of ASU 2016-02 on the Company’s consolidated financial statements, including the anticipated gross up for lease assets and lease liabilities on the consolidated statement of financial condition. The standard is effective for the Company on January 1, 2019 under a modified retrospective approach.

Cash and Cash Equivalents

Cash and Cash Equivalents	6 Months Ended
	Jun. 30, 2018
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents	Cash and Cash Equivalents The carrying values of the Company's cash and cash equivalents are as follows: As of June 30, As of December 31, 2018 2017 (in thousands) (unaudited) Cash $ 103,690 $ 70,459 Cash equivalents 41,769 193,315 Restricted cash - letters of credit 3,827 3,872 Total cash and cash equivalents $ 149,286 $ 267,646 The carrying value of the Company's cash equivalents approximates fair value. See "Note 4 — Fair Value of Financial Instruments". Letters of credit are secured by cash held on deposit.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments Assets and liabilities are classified in their entirety based on their lowest level of input that is significant to the fair value measurement. For the three and six month periods ended June 30, 2018 and the year ended December 31, 2017 , the Company had Level 1 assets and Level 3 liabilities measured at fair value. The following tables set forth the measurement at fair value on a recurring basis of the investments in money market funds, short-term cash instruments and U.S. government securities. The securities are categorized as a Level 1 asset, as their valuation is based on quoted prices for identical assets in active markets. See "Note 3 — Cash and Cash Equivalents". Assets Measured at Fair Value on a Recurring Basis as of June 30, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance as of June 30, 2018 (in thousands, unaudited) Assets Cash and cash equivalents $ 41,769 $ — $ — $ 41,769 Total $ 41,769 $ — $ — $ 41,769 Assets Measured at Fair Value on a Recurring Basis as of December 31, 2017 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance as of December 31, 2017 (in thousands) Assets Cash and cash equivalents $ 193,315 $ — $ — $ 193,315 Total $ 193,315 $ — $ — $ 193,315 In connection with the acquisition in April 2015 of Cogent Partners, LP and its affiliates ("Cogent") (now known as the secondary capital advisory business), the Company agreed to pay to the sellers in the future $18.9 million in cash and 334,048 shares of Greenhill common stock if certain agreed revenue targets are achieved (the "Earnout"). The cash payment and the issuance of common shares related to the Earnout will be made if secondary capital advisory revenues of $80.0 million or more are earned during either the two year period ending on the second anniversary of the closing or the two year period ending on the fourth anniversary of the closing. The revenue generated by the secondary capital advisory business for the first two year period ended March 31, 2017 was slightly less than required to achieve the Cogent earnout. If the revenue target is achieved during the second two year period ending on March 31, 2019, the contingent consideration will be paid promptly after that date. If the revenue target is not achieved during the remaining two year earnout period, a payment will not be made. Based on the revenue generated by the secondary fund placement business since April 1, 2017, it is highly likely that the revenue target for the second two-year period will be achieved. The fair value of the contingent cash consideration was valued on the date of the acquisition at $13.1 million and is remeasured quarterly based on a probability weighted present value discount that the revenue target may be achieved. At June 30, 2018 , based on the estimated probability of achievement and the present value of the remaining term, the contingent cash consideration was valued at $17.4 million . Due to the remeasurement of the likelihood of achievement of the Earnout, for the three and six month periods ended June 30, 2018 , the Company recognized increases in other operating expenses of $2.7 million and $3.6 million , respectively. For the three and six month periods ended June 30, 2017 , the Company recognized decreases in other operating expenses of $1.5 million and $7.5 million , respectively. See "Note 8 — Earnings per Share". The following tables set forth the measurement at fair value on a recurring basis of the contingent cash consideration due to the selling unitholders of Cogent related to the Earnout. The liability arose as a result of the acquisition of Cogent and is categorized as a Level 3 liability, which is remeasured each quarterly period based on the probability of achieving the target revenue threshold and weighted average discount rate as discussed below. Liabilities Measured at Fair Value on a Recurring Basis as of June 30, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance as of June 30, 2018 (in thousands, unaudited) Liabilities Contingent obligation due selling unitholders of Cogent $ — $ — $ 17,354 $ 17,354 Total $ — $ — $ 17,354 $ 17,354 Liabilities Measured at Fair Value on a Recurring Basis as of December 31, 2017 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance as of December 31, 2017 (in thousands) Liabilities Contingent obligation due selling unitholders of Cogent $ — $ — $ 13,763 $ 13,763 Total $ — $ — $ 13,763 $ 13,763 Changes in Level 3 liabilities measured at fair value on a recurring basis for the three and six month periods ended June 30, 2018 are as follows: Opening Balance as of April 1, 2018 Total realized and unrealized gains (losses) included in Net Income Unrealized gains (losses) included in Other Comprehen-sive Income Purchases Issues Sales Settlements Closing Balance as of June 30, 2018 Unrealized gains (losses) for Level 3 liabilities outstanding at June 30, 2018 (in thousands, unaudited) Liabilities Contingent obligation due selling unitholders of Cogent $ 14,673 $ (2,681 ) $ — $ — $ — $ — $ — $ 17,354 $ (2,681 ) Total $ 14,673 $ (2,681 ) $ — $ — $ — $ — $ — $ 17,354 $ (2,681 ) Opening Balance as of January 1, 2018 Total realized and unrealized gains (losses) included in Net Income Unrealized gains (losses) included in Other Comprehen-sive Income Purchases Issues Sales Settlements Closing Balance as of June 30, 2018 Unrealized gains (losses) for Level 3 liabilities outstanding at June 30, 2018 (in thousands, unaudited) Liabilities Contingent obligation due selling unitholders of Cogent $ 13,763 $ (3,591 ) $ — $ — $ — $ — $ — $ 17,354 $ (3,591 ) Total $ 13,763 $ (3,591 ) $ — $ — $ — $ — $ — $ 17,354 $ (3,591 ) Changes in Level 3 liabilities measured at fair value on a recurring basis for the three and six month periods ended June 30, 2017 are as follows: Opening Balance as of April 1, 2017 Total realized and unrealized gains (losses) included in Net Income Unrealized gains (losses) included in Other Comprehen-sive Income Purchases Issues Sales Settlements Closing Balance as of June 30, 2017 Unrealized gains (losses) for Level 3 liabilities outstanding at June 30, 2017 (in thousands, unaudited) Liabilities Contingent obligation due to selling unitholders of Cogent $ 9,090 $ 1,508 $ — $ — $ — $ — $ — $ 7,582 $ 1,508 Total $ 9,090 $ 1,508 $ — $ — $ — $ — $ — $ 7,582 $ 1,508 Opening Balance as of January 1, 2017 Total realized and unrealized gains (losses) included in Net Income Unrealized gains (losses) included in Other Comprehen-sive Income Purchases Issues Sales Settlements Closing Balance as of June 30, 2017 Unrealized gains (losses) for Level 3 liabilities outstanding at June 30, 2017 (in thousands, unaudited) Liabilities Contingent obligation due to selling unitholders of Cogent $ 15,095 $ 7,513 $ — $ — $ — $ — $ — $ 7,582 $ 7,513 Total $ 15,095 $ 7,513 $ — $ — $ — $ — $ — $ 7,582 $ 7,513 Realized and unrealized gains (losses) are reported as a component of other operating expenses in the condensed consolidated statements of operations. The following table presents quantitative information about the significant unobservable inputs utilized by the Company in the fair value measure of Level 3 liabilities measured at fair value on a recurring basis, as of June 30, 2018 : Fair Value as of June 30, 2018 Valuation Technique(s) Unobservable Input(s) Range (Weighted Average) (in thousands, unaudited) Liabilities Contingent obligation due selling unitholders of Cogent $ 17,354 Present value of expected payments Discount rate 11.8 % Forecast revenue (a) _____________________________________________ (a) The Company's estimate of contingent consideration as of June 30, 2018 was principally based on the acquired business' actual and projected revenue generation from April 1, 2017 through March 31, 2019. Valuation Processes - Level 3 Measurements - The Company utilizes a valuation technique based on a present value method applied to the probability of achieving a range of potential revenue outcomes. The valuation was conducted by the Company. The Company updates unobservable inputs each reporting period and has a formal process in place to review changes in fair value. Sensitivity Analysis - Level 3 Measurements - The significant unobservable inputs used in determining fair value are the discount rate and forecast revenue information. Significant increases (decreases) in the discount rate would have resulted in a lower (higher) fair value measurement, respectively. Significant increases (decreases) in the forecast revenue information would result in a higher (lower) fair value measurement, respectively. For all significant unobservable inputs used in the fair value measurement of the Level 3 liabilities, a change in one of the inputs would not necessarily result in a directionally similar change in the other inputs.

Related Parties

Related Parties	6 Months Ended
	Jun. 30, 2018
Related Party Transactions [Abstract]
Related Parties	Related Parties At June 30, 2018 and December 31, 2017 , the Company had no amounts receivable from or payable to related parties. The Company subleases airplane and office space to a firm owned by the Chairman of the Company. The Company recognized rent reimbursements of less than $0.1 million for each of the three and six month periods ended June 30, 2018 and 2017 .

Loan Facilities

Loan Facilities	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Bank Loan Facilities	Loan Facilities In October 2017, as part of a recapitalization plan, the Company entered into a new credit agreement with a syndicate of lenders, who lent a principal amount of $350.0 million under a five -year secured term loan facility ("Term Loan Facility") and provided a three -year secured revolving credit facility ("Revolving Loan Facility") for $20.0 million , which was undrawn at closing. The Term Loan Facility and the Revolving Loan Facility together are referred to as the "Secured Loan Facilities". In conjunction with the borrowings under the Secured Loan Facilities, the Company incurred expenses of $11.5 million , consisting of original issue discount of $1.75 million and deferred financing costs of $9.8 million , which were recorded as a reduction in the initial carrying value of the Term Loan Facility. These costs are being amortized into interest expense over the lives of the obligations. In conjunction with the borrowing of the Term Loan Facility, the Company used a portion of the proceeds to repay in full outstanding borrowings under the previously existing revolving bank loan facility. As of June 30, 2018 and December 31, 2017 , the Term Loan Facility carrying values were $331.5 million and $339.0 million , respectively, and no amounts were outstanding under the Revolving Loan Facility at either date. The carrying value of the Term Loan Facility, excluding the unamortized debt issuance costs that are presented as a reduction to the debt principal balance, approximated the fair value. As the borrowings are not accounted for at fair value, their fair value is not included in the Company's fair value hierarchy in "Note 4 — Fair Value of Financial Instruments," however, had these borrowings been included, they would have been classified in Level 2. For the three and six months ended June 30, 2018 , the Company incurred interest expense of $5.6 million and $10.9 million , respectively, of which $0.6 million and $1.2 million related to the amortization of the debt issuance costs. For the three and six months ended June 30, 2017 , the Company incurred interest expense of $0.8 million and $1.6 million , respectively, related to bank loan borrowings, which were repaid as part of the October 2017 recapitalization. Borrowings under the Secured Loan Facilities bear interest at either the U.S. Prime Rate plus 2.75% or LIBOR plus 3.75% . Borrowings under the Secured Loan Facilities had a weighted average interest rate for the six months ended June 30, 2018 of 5.55% . The Term Loan Facility requires quarterly principal amortization payments of $4.375 million , which began on March 31, 2018 and continue through September 30, 2018, and $8.75 million (or $35.0 million annually) beginning December 31, 2018 through September 30, 2022, with the remaining balance of the Term Loan Facility due at maturity on October 12, 2022. In addition, beginning for the year ended December 31, 2018, the Company is required to make annual repayments of principal on the Term Loan Facility within ninety days of year end of up to 50% (determined based on the net leverage ratio) of its annual excess cash flow as defined in the credit agreement. The Company is also required to repay certain amounts of the Term Loan Facility in connection with the non-ordinary course sale of assets, receipt of insurance proceeds, and the issuance of debt obligations, subject to certain exceptions. During the six months ended June 30, 2018 , the Company made mandatory principal payments of $8.75 million . All mandatory repayments of the Term Loan Facility will be applied without penalty or premium. Voluntary prepayments of borrowings under the Term Loan Facility will be permitted. In the event that all or any portion of the Term Loan Facility is prepaid or refinanced or repriced through any amendment prior to April 12, 2019, such prepayment, refinancing, or repricing will be at 101.0% of the principal amount so prepaid, refinanced or repriced. The Term Loan Facility and Revolving Loan Facility are both guaranteed by the Company's existing and subsequently acquired or organized wholly-owned U.S. restricted subsidiaries (excluding any registered broker-dealers) and secured with a first priority perfected security interest in certain domestic assets and 100% of the capital stock of each U.S. subsidiary and 65% of the capital stock of each non-U.S. subsidiary, subject to certain exclusions which, for the avoidance of doubt, such security interest shall not include any assets of regulated subsidiaries that are not permitted to be pledged by law, statute or regulation, including cash held by regulated subsidiaries and any other capital required to meet and maintain regulatory capital requirements. The credit facilities contain certain covenants that limit the Company's ability above certain permitted amounts to incur additional indebtedness, make certain acquisitions, pay dividends and repurchase shares. The Term Loan Facility does not have financial covenants and the Revolving Loan Facility is subject to a springing total net leverage ratio financial covenant, subject to certain step downs, if the Company's borrowings under the revolving loan facility exceed $12.5 million . The Company is also subject to certain other non-financial covenants. At June 30, 2018 , the Company was compliant with all loan covenants.

Equity

Equity	6 Months Ended
	Jun. 30, 2018
Stockholders' Equity Note [Abstract]
Equity	Equity On June 20, 2018, a dividend of $0.05 per share was paid to stockholders of record on June 6, 2018. For the six months ended June 30, 2018 , dividend payments of $0.10 per share were paid to stockholders and dividend equivalent payments of $0.6 million were paid to holders of restricted stock units. During the six months ended June 30, 2017 , dividend payments of $0.90 per share were paid to stockholders and dividend equivalent payments of $4.1 million were paid to holders of restricted stock units. In October 2017, the Company commenced a recapitalization plan to repurchase up to $285.0 million of its common stock. During the six months ended June 30, 2018 , the Company repurchased 4,886,382 common shares through a modified Dutch auction tender and open market transactions at an average price of $22.87 , for a total cost of $111.8 million . During the six months ended June 30, 2018 , 1,065,587 restricted stock units vested and were settled in shares of common stock, of which the Company is deemed to have repurchased 397,580 shares at an average price of $18.99 per share for a total cost of $7.5 million in conjunction with the payment of tax liabilities in respect of stock delivered to its employees in settlement of restricted stock units. During the six months ended June 30, 2017 , 1,049,998 restricted stock units vested and were settled in shares of common stock, of which the Company is deemed to have repurchased 432,121 shares at an average price of $29.46 per share for a total cost of $12.7 million in conjunction with the payment of tax liabilities in respect of stock delivered to its employees in settlement of restricted stock units.

Earnings per Share

Earnings per Share	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share The computations of basic and diluted EPS are set forth below: For the Three Months Ended June 30, For the Six Months Ended June 30, 2018 2017 2018 2017 (in thousands, except per share amounts, unaudited) Numerator for basic and diluted EPS — net income $ 10,513 $ 6,245 $ 16,881 $ 5,499 Denominator for basic EPS — weighted average number of shares 26,993 31,934 28,546 32,151 Add — dilutive effect of: Restricted stock units 929 (1) 44 (2) 679 (1) 100 (2) Denominator for diluted EPS — weighted average number of shares and dilutive securities 27,922 31,977 29,225 32,252 Earnings per share: Basic EPS $ 0.39 $ 0.20 $ 0.59 $ 0.17 Diluted EPS $ 0.38 $ 0.20 $ 0.58 $ 0.17 The weighted number of shares and dilutive potential shares do not include 334,048 shares of common stock, which will be issued to certain selling unitholders of Cogent, following the fourth anniversary of the acquisition if the revenue target related to the Earnout is achieved. In the event that the revenue target is achieved prior to March 31, 2019, such shares will be included in the Company’s share count in the period the revenue target is achieved. If the revenue target is not achieved, such shares of common stock will not be issued. See "Note 4 — Fair Value of Financial Instruments". ________________________ (1) Excludes 563,778 and 619,235 outstanding restricted stock units that were antidilutive under the treasury stock method for the three and six months ended June 30, 2018 , respectively, and thus were not included in the above calculation. The incremental shares that could be included in the diluted EPS calculation in future periods will vary based on a variety of factors, including the future share price and the amount of unrecognized compensation cost. The incremental shares included, if any, would be less than the number of outstanding restricted stock units. (2) Excludes 1,436,970 and 1,386,443 outstanding restricted stock units that were antidilutive under the treasury stock method for the three and six months ended June 30, 2017 , respectively, and thus were not included in the above calculation. The incremental shares that could be included in the diluted EPS calculation in future periods will vary based on a variety of factors, including the future share price and the amount of unrecognized compensation cost. The incremental shares included, if any, would be less than the number of outstanding restricted stock units.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company is subject to U.S. federal, foreign, state and local corporate income taxes and its effective tax rate varies depending on the jurisdiction in which the income is earned. Effective in 2017, the Company was subject to a new accounting pronouncement which requires it to record a charge or benefit in its income tax provision for the tax effect of the difference between the grant date value of restricted stock units and the market value of such awards at the time of vesting. The provisions for income taxes for the six months ended June 30, 2018 and 2017 include net charges of $4.4 million and $1.5 million , respectively, related to the tax effect of the vesting of restricted stock units at a market value below their grant price. In December 2017, the Tax Cuts and Jobs Act (the “Tax Act”) was enacted and made significant changes to U.S. corporate income tax laws by, among other things, lowering the corporate income tax rate from 35% to 21% beginning in 2018 and implementing a territorial-type tax system with a minimum tax for certain foreign earnings beginning in 2018. Under the current accounting requirements, the Company revalued its deferred tax assets and liabilities using the lower corporate rate as of the effective date of the legislation in 2017. In addition, the Company did not incur a one-time repatriation toll charge associated with the implementation of the territorial-type system because it was allowed to offset cumulative foreign losses in some of its jurisdictions against the cumulative foreign earnings in other jurisdictions. Based on the Company's historical taxable income and its expectation for taxable income in the future, management expects that its largest deferred tax asset, which relates principally to compensation expense deducted for book purposes but not yet deducted for tax purposes, will be realized as offsets to future taxable income. Any gain or loss resulting from the translation of deferred taxes for foreign affiliates is included in the foreign currency translation adjustment incorporated as a component of other comprehensive income (loss), net of tax, in the condensed consolidated statements of changes in stockholders' equity and the condensed consolidated statements of comprehensive income. The Company is subject to the income tax laws of the United States, its states and municipalities, and those of the foreign jurisdictions in which the Company operates. These laws are complex, and the manner in which they apply to the taxpayer's facts is sometimes open to interpretation. Management must make judgments in assessing the likelihood that a tax position will be sustained upon examination by the taxing authorities based on the technical merits of the tax position. In the normal course of business, the Company may be under audit in one or more of its jurisdictions in an open tax year for that particular jurisdiction. As of June 30, 2018 , the Company does not expect any material changes in its tax provision related to any current or future audits.

Regulatory Requirements

Regulatory Requirements	6 Months Ended
	Jun. 30, 2018
Regulatory Capital Requirements [Abstract]
Regulatory Requirements	Regulatory Requirements Certain subsidiaries of the Company are subject to various regulatory requirements in the United States, United Kingdom, Australia and certain other jurisdictions, which specify, among other requirements, minimum net capital requirements for registered broker-dealers. G&Co is subject to the SEC’s Uniform Net Capital requirements under Rule 15c3-1 (the “Rule”), which specifies, among other requirements, minimum net capital requirements for registered broker-dealers. The Rule requires G&Co to maintain a minimum net capital of the greater of $5,000 or 1/15 of aggregate indebtedness, as defined in the Rule. As of June 30, 2018 , G&Co’s net capital was $10.6 million , which exceeded its requirement by $8.9 million . G&Co’s aggregate indebtedness to net capital ratio was 2.4 to 1 at June 30, 2018 . Certain distributions and other capital withdrawals of G&Co are subject to certain notifications and restrictive provisions of the Rule. GC LP is also subject to the Rule. GCI, GCE and the European affiliate of GC LP are subject to capital requirements of the FCA. Greenhill Australia is subject to capital requirements of the ASIC. We are also subject to certain capital regulatory requirements in other jurisdictions. As of June 30, 2018 , GCI, GCE, GC LP, Greenhill Australia, and our other regulated operations were in compliance with local capital adequacy requirements.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The Company evaluates subsequent events through the date on which the financial statements are issued. On August 2, 2018 , the Board of Directors of the Company declared a quarterly dividend of $0.05 per share. The dividend will be payable on September 19, 2018 to the common stockholders of record on September 5, 2018 .

Summary of Significant Accoun20

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Basis of Financial Information	Basis of Financial Information These condensed consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States (U.S. GAAP), which require management to make estimates and assumptions regarding future events that affect the amounts reported in our financial statements and these footnotes, including investment valuations, compensation accruals, income tax expense related to the Tax Cuts and Jobs Act, and other matters. Management believes that the estimates used in preparing its condensed consolidated financial statements are reasonable and prudent. Actual results could differ materially from those estimates. Certain reclassifications have been made to prior year information to conform to current year presentation. The condensed consolidated financial statements of the Company include all consolidated accounts of Greenhill & Co., Inc. and all other entities in which the Company has a controlling interest after eliminations of all significant inter-company accounts and transactions. These condensed consolidated financial statements are unaudited and should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2017 included in the Company's Annual Report on Form 10-K filed with the SEC. The condensed consolidated financial information as of December 31, 2017 has been derived from audited consolidated financial statements not included herein. The results of operations for interim periods are not necessarily indicative of results for the entire year.
Revenue Recognition	Revenue Recognition Advisory Revenues The Company adopted ASU 2014-09, Revenue from Contracts with Customers, on January 1, 2018. The Company’s accounting policies for advisory revenues following the adoption of this ASU are included below. The Company's accounting policies for advisory revenues prior to adopting ASU 2014-09 are included in “Note 2 — Summary of Significant Accounting Policies” in the Company's 2017 Annual Report on Form 10-K filed with the SEC. The Company recognizes revenue when (or as) services are transferred to clients. Revenue is recognized based on the amount of consideration that management expects to receive in exchange for these services in accordance with the terms of the contract with the client. To determine the amount and timing of revenue recognition, the Company must (1) identify the contract with the client, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when (or as) the Company satisfies a performance obligation. The Company generally recognizes advisory fee revenues for mergers and acquisitions engagements at the earlier of the announcement date or transaction date, as the performance obligation is typically satisfied at such time. Upfront fees and certain retainer fees are generally deferred until the announcement or transaction date as they are considered constrained (subject to significant reversal) prior to the announcement or transaction date. Fairness opinion fees are recognized when the opinion is delivered. The Company recognizes advisory fee revenues for financing advisory and restructuring engagements as the services are provided to the client, based on terms of the engagement letter. In such arrangements, the Company’s performance obligations are to provide financial and strategic advice throughout an engagement. The Company recognizes revenues for capital advisory fees when (1) the commitment of capital is secured (primary capital raising transactions) or the sale or transfer of the capital interest occurs (secondary market transactions) and (2) the fees are earned from the client in accordance with terms of the engagement letter. Upfront fees and certain retainer fees are deferred until the commitment is secured or the sale or transfer of the capital interest occurs, as the fees are considered constrained (subject to significant reversal) prior to such time. As a result of the deferral of certain fees, including the cumulative effect adjustment of $10.2 million recorded upon adoption of ASU 2014-09, deferred revenue (also known as contract liabilities) was $10.4 million and $12.3 million as of June 30, 2018 and January 1, 2018, respectively. Deferred revenue is included in accounts payable and accrued expenses in the condensed consolidated statements of financial condition. During the six months ended June 30, 2018 , the Company recognized $8.1 million of advisory fee revenues that were included in the deferred revenue (contract liabilities) balance at adoption. The Company’s clients reimburse certain expenses incurred by the Company in the conduct of advisory engagements. Client reimbursements totaled $2.2 million and $1.0 million for the three months ended June 30, 2018 and 2017 , respectively, and $3.4 million and $2.1 million for the six months ended June 30, 2018 and 2017 . Such reimbursements were reported as advisory revenues and operating expenses for the three and six months ended June 30, 2018 and as a reduction to operating expenses for the three and six months ended June 30, 2017 , with no impact to operating income in the periods presented. Investment Revenues Investment revenues consist of gains (or losses) on the Company's investments in certain merchant banking funds and interest income. The Company recognizes revenue on its investments in merchant banking funds based on its allocable share of realized and unrealized gains (or losses) reported by such funds. The Company’s revenue recognition for investment revenues, which represent less than 1% of total revenues, was not impacted by the adoption of ASU 2014-09.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company’s cash and cash equivalents consist of (i) cash held on deposit with financial institutions, (ii) cash equivalents and (iii) restricted cash. The Company maintains its cash and cash equivalents with financial institutions with high credit ratings. The Company considers all highly liquid investments with a maturity date of three months or less, when purchased, to be cash equivalents. Cash equivalents primarily consist of money market funds, commercial paper, Treasury bills and short-term government bonds and are carried at cost plus accrued interest, which approximates the fair value due to the short-term nature of these investments. Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. See "Note 3 — Cash and Cash Equivalents".
Advisory Fees Receivables	Advisory Fees Receivable Receivables are stated net of an allowance for doubtful accounts. The estimate for the allowance for doubtful accounts is derived by the Company by utilizing past client transaction history and an assessment of the client’s creditworthiness. The Company recorded a bad debt expense of $0.3 million for the three and six month periods ended June 30, 2018 and a bad debt expense of $0.8 million for the three and six month periods ended June 30, 2017 . Included in the advisory fees receivable balance at June 30, 2018 and December 31, 2017 were $25.4 million and $29.3 million , respectively, of long term receivables related to primary capital advisory engagements which are generally paid in installments over a period of three years . Included as a component of investment revenues is interest income related to primary capital advisory engagements of $0.2 million for the each of the three months ended June 30, 2018 and 2017 , and $0.4 million for each of the six months ended June 30, 2018 and 2017 . Credit risk related to advisory fees receivable is disbursed across a large number of clients located in various geographic areas. The Company controls credit risk through credit approvals and monitoring procedures but does not require collateral to support accounts receivable.
Goodwill	Goodwill Goodwill is the cost in excess of the fair value of identifiable net assets at the acquisition date. The Company tests its goodwill for impairment at least annually. An impairment loss is triggered if the estimated fair value of an operating unit is less than the estimated net book value. Such loss is calculated as the difference between the estimated fair value of goodwill and its carrying value. Goodwill is translated at the rate of exchange prevailing at the end of the periods presented in accordance with the accounting guidance for foreign currency translation. Any translation gain or loss is included in the foreign currency translation adjustment, which is included as a component of other comprehensive income (loss) in the condensed consolidated statements of changes in stockholders' equity.
Other Assets	Other Assets Included in other assets in the condensed consolidated statements of financial condition are the Company's investments in merchant banking funds, which are recorded under the equity method of accounting based upon the Company's proportionate share of the estimated fair value of the underlying merchant banking fund's net assets. Other assets also include prepaid compensation awards that require a future service period and are subject to clawbacks if the individual ceases employment prior to a determined date. The awards are amortized over the required service period, which generally does not exceed one year. Other prepaid expenses, rent deposits, intangible assets and other tangible assets are also included in other assets.
Compensation Payable	Compensation Payable Included in compensation payable are discretionary compensation awards comprised of accrued cash bonuses and long-term incentive compensation, consisting of deferred cash retention awards, which are non-interest bearing, and generally amortized over a three to five year service period after the date of grant.
Restricted Stock Units	Restricted Stock Units The Company accounts for its share-based compensation payments by recording the fair value of restricted stock units granted to employees as compensation expense. The restricted stock units are generally amortized over a four to five -year service period following the date of grant. Compensation expense is determined based upon the fair value of the Company’s common stock at the date of grant. In certain circumstances the Company issues share-based compensation, which is contingent on achievement of certain performance targets. Compensation expense for performance-based awards begins at the time it is deemed probable that the performance target will be achieved and is amortized into expense over the remaining service period. As the Company expenses the awards, the restricted stock units recognized are recorded within stockholders' equity. The restricted stock units are reclassified into common stock and additional paid-in capital upon vesting. The Company records as treasury stock the repurchase of stock delivered to its employees in settlement of tax liabilities incurred upon the vesting of restricted stock units. The Company records dividend equivalent payments on outstanding restricted stock units eligible for such payment as a dividend payment and a charge to stockholders' equity.
Earnings per Share	Earnings per Share The Company calculates basic earnings per share (“EPS”) by dividing net income by the sum of (i) the weighted average number of shares outstanding for the period and (ii) the weighted average number of shares deemed issuable due to the vesting of restricted stock units for accounting purposes. See "Note 7 — Equity". The Company calculates diluted EPS by dividing net income by the sum of (i) basic shares per above and (ii) the dilutive effect of the common stock deliverable pursuant to restricted stock units for which future service is required. Under the treasury method, the number of shares issuable upon the vesting of restricted stock units included in the calculation of diluted EPS is the excess, if any, of the number of shares expected to be issued, less the number of shares that could be repurchased by the Company with the proceeds to be received upon settlement at the average market closing price during the reporting period. See "Note 8 — Earnings per Share".
Provision for Taxes	Provision for Taxes The Company accounts for taxes in accordance with the accounting guidance for income taxes which requires the recognition of tax benefits or expenses on the temporary differences between the financial reporting and tax bases of its assets and liabilities. The Company follows the guidance for income taxes in recognizing, measuring, presenting and disclosing in its financial statements uncertain tax positions taken or expected to be taken on its income tax returns. Income tax expense is based on pre-tax accounting income, including adjustments made for the recognition or derecognition related to uncertain tax positions. The recognition or derecognition of income tax expense related to uncertain tax positions is determined under the guidance, and the Company's policy is to treat interest and penalties related to uncertain tax positions as part of pre-tax income. Deferred tax assets and liabilities are recognized for the future tax attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in earnings in the period of change. Management applies the “more-likely-than-not criteria” when determining tax benefits.
Foreign Currency Translation	Foreign Currency Translation Assets and liabilities denominated in foreign currencies have been translated at rates of exchange prevailing at the end of the periods presented in accordance with the accounting guidance for foreign currency translation. Income and expenses transacted in foreign currency have been translated at average monthly exchange rates during the period. Translation gains and losses are included in the foreign currency translation adjustment, which is included as a component of other comprehensive income (loss) in the condensed consolidated statements of changes in stockholders' equity. Foreign currency transaction gains and losses are included in the condensed consolidated statements of operations in other operating expenses.
Financial Instruments and Fair Value	Financial Instruments and Fair Value The Company accounts for financial instruments measured at fair value in accordance with accounting guidance for fair value measurements and disclosures which establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy under the pronouncement are described below: Basis of Fair Value Measurement Level 1 – Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; Level 2 – Quoted prices in markets that are not active or financial instruments for which all significant inputs are observable, either directly or indirectly; and Level 3 – Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. In determining the appropriate levels, the Company performs an analysis of the assets and liabilities that are subject to these disclosures. At each reporting period, all assets and liabilities for which the fair value measurement is based on significant unobservable inputs or instruments which trade infrequently and therefore have little or no price transparency are classified as Level 3. Transfers between levels are recognized as of the end of the period in which they occur. See "Note 4 — Fair Value of Financial Instruments".
Property and Equipment	Property and Equipment Property and equipment is stated at cost less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the life of the assets. Amortization of leasehold improvements is computed using the straight-line method over the lesser of the life of the asset or the remaining term of the lease. Estimated useful lives of the Company’s fixed assets are generally as follows: Aircraft – 7 years Equipment – 5 years Furniture and fixtures – 7 years Leasehold improvements – the lesser of 10 years or the remaining lease term
Business Information	Business Information The Company's activities as an investment banking firm constitute a single business segment, with substantially all revenues generated from advisory services, which includes engagements relating to mergers and acquisitions, financing advisory and restructuring, and capital advisory services. The Company earns less than 1% of its revenues from interest income and investment gains (losses) on investments.
Recently Adopted Accounting Pronouncements and Accounting Developments	Recently Adopted Accounting Pronouncements In May 2014, the FASB issued ASU 2014-09 "Revenue from Contracts with Customers" codifying ASC 606, Revenue Recognition - Revenue from Contracts with Customers, which supersedes the guidance in former ASC 605, Revenue Recognition. The Company adopted this standard on January 1, 2018 utilizing the modified retrospective approach and applied the standard to contracts that were not completed at this time. Upon adoption, certain revenues that were previously recognized as services were provided changed to either point in time recognition or over the term of an engagement. This change in the Company's revenue recognition policy created deferred revenues (also known as contract liabilities) that will be recognized at a point in time as performance obligations are met. The cumulative effect of adopting this ASU on January 1, 2018 was a net decrease to retained earnings of $7.6 million . The Company also changed the presentation of certain reimbursed costs from a net presentation prior to adoption to a gross presentation following adoption. Accounting Developments In February 2016, the FASB issued ASU No. 2016-02, Leases ("ASU 2016-02"). ASU 2016-02 requires the recognition of lease assets and lease liabilities for operating leases, among other changes. This ASU also requires expanded disclosures about the nature and terms of leases. Management is currently evaluating the impact of the future adoption of ASU 2016-02 on the Company’s consolidated financial statements, including the anticipated gross up for lease assets and lease liabilities on the consolidated statement of financial condition. The standard is effective for the Company on January 1, 2019 under a modified retrospective approach.

Cash and Cash Equivalents (Tabl

Cash and Cash Equivalents (Tables)	6 Months Ended
	Jun. 30, 2018
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	The carrying values of the Company's cash and cash equivalents are as follows: As of June 30, As of December 31, 2018 2017 (in thousands) (unaudited) Cash $ 103,690 $ 70,459 Cash equivalents 41,769 193,315 Restricted cash - letters of credit 3,827 3,872 Total cash and cash equivalents $ 149,286 $ 267,646

Fair Value of Financial Instr22

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements, Recurring and Nonrecurring	Liabilities Measured at Fair Value on a Recurring Basis as of June 30, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance as of June 30, 2018 (in thousands, unaudited) Liabilities Contingent obligation due selling unitholders of Cogent $ — $ — $ 17,354 $ 17,354 Total $ — $ — $ 17,354 $ 17,354 Liabilities Measured at Fair Value on a Recurring Basis as of December 31, 2017 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance as of December 31, 2017 (in thousands) Liabilities Contingent obligation due selling unitholders of Cogent $ — $ — $ 13,763 $ 13,763 Total $ — $ — $ 13,763 $ 13,763 Assets Measured at Fair Value on a Recurring Basis as of June 30, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance as of June 30, 2018 (in thousands, unaudited) Assets Cash and cash equivalents $ 41,769 $ — $ — $ 41,769 Total $ 41,769 $ — $ — $ 41,769 Assets Measured at Fair Value on a Recurring Basis as of December 31, 2017 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance as of December 31, 2017 (in thousands) Assets Cash and cash equivalents $ 193,315 $ — $ — $ 193,315 Total $ 193,315 $ — $ — $ 193,315
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	Changes in Level 3 liabilities measured at fair value on a recurring basis for the three and six month periods ended June 30, 2018 are as follows: Opening Balance as of April 1, 2018 Total realized and unrealized gains (losses) included in Net Income Unrealized gains (losses) included in Other Comprehen-sive Income Purchases Issues Sales Settlements Closing Balance as of June 30, 2018 Unrealized gains (losses) for Level 3 liabilities outstanding at June 30, 2018 (in thousands, unaudited) Liabilities Contingent obligation due selling unitholders of Cogent $ 14,673 $ (2,681 ) $ — $ — $ — $ — $ — $ 17,354 $ (2,681 ) Total $ 14,673 $ (2,681 ) $ — $ — $ — $ — $ — $ 17,354 $ (2,681 ) Opening Balance as of January 1, 2018 Total realized and unrealized gains (losses) included in Net Income Unrealized gains (losses) included in Other Comprehen-sive Income Purchases Issues Sales Settlements Closing Balance as of June 30, 2018 Unrealized gains (losses) for Level 3 liabilities outstanding at June 30, 2018 (in thousands, unaudited) Liabilities Contingent obligation due selling unitholders of Cogent $ 13,763 $ (3,591 ) $ — $ — $ — $ — $ — $ 17,354 $ (3,591 ) Total $ 13,763 $ (3,591 ) $ — $ — $ — $ — $ — $ 17,354 $ (3,591 ) Changes in Level 3 liabilities measured at fair value on a recurring basis for the three and six month periods ended June 30, 2017 are as follows: Opening Balance as of April 1, 2017 Total realized and unrealized gains (losses) included in Net Income Unrealized gains (losses) included in Other Comprehen-sive Income Purchases Issues Sales Settlements Closing Balance as of June 30, 2017 Unrealized gains (losses) for Level 3 liabilities outstanding at June 30, 2017 (in thousands, unaudited) Liabilities Contingent obligation due to selling unitholders of Cogent $ 9,090 $ 1,508 $ — $ — $ — $ — $ — $ 7,582 $ 1,508 Total $ 9,090 $ 1,508 $ — $ — $ — $ — $ — $ 7,582 $ 1,508 Opening Balance as of January 1, 2017 Total realized and unrealized gains (losses) included in Net Income Unrealized gains (losses) included in Other Comprehen-sive Income Purchases Issues Sales Settlements Closing Balance as of June 30, 2017 Unrealized gains (losses) for Level 3 liabilities outstanding at June 30, 2017 (in thousands, unaudited) Liabilities Contingent obligation due to selling unitholders of Cogent $ 15,095 $ 7,513 $ — $ — $ — $ — $ — $ 7,582 $ 7,513 Total $ 15,095 $ 7,513 $ — $ — $ — $ — $ — $ 7,582 $ 7,513
Fair Value Inputs, Liabilities, Quantitative Information	The following table presents quantitative information about the significant unobservable inputs utilized by the Company in the fair value measure of Level 3 liabilities measured at fair value on a recurring basis, as of June 30, 2018 : Fair Value as of June 30, 2018 Valuation Technique(s) Unobservable Input(s) Range (Weighted Average) (in thousands, unaudited) Liabilities Contingent obligation due selling unitholders of Cogent $ 17,354 Present value of expected payments Discount rate 11.8 % Forecast revenue (a) _____________________________________________ (a) The Company's estimate of contingent consideration as of June 30, 2018 was principally based on the acquired business' actual and projected revenue generation from April 1, 2017 through March 31, 2019.

Earnings per Share (Tables)

Earnings per Share (Tables)	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Computations of Basic and Diluted Earnings Per Share	The computations of basic and diluted EPS are set forth below: For the Three Months Ended June 30, For the Six Months Ended June 30, 2018 2017 2018 2017 (in thousands, except per share amounts, unaudited) Numerator for basic and diluted EPS — net income $ 10,513 $ 6,245 $ 16,881 $ 5,499 Denominator for basic EPS — weighted average number of shares 26,993 31,934 28,546 32,151 Add — dilutive effect of: Restricted stock units 929 (1) 44 (2) 679 (1) 100 (2) Denominator for diluted EPS — weighted average number of shares and dilutive securities 27,922 31,977 29,225 32,252 Earnings per share: Basic EPS $ 0.39 $ 0.20 $ 0.59 $ 0.17 Diluted EPS $ 0.38 $ 0.20 $ 0.58 $ 0.17 The weighted number of shares and dilutive potential shares do not include 334,048 shares of common stock, which will be issued to certain selling unitholders of Cogent, following the fourth anniversary of the acquisition if the revenue target related to the Earnout is achieved. In the event that the revenue target is achieved prior to March 31, 2019, such shares will be included in the Company’s share count in the period the revenue target is achieved. If the revenue target is not achieved, such shares of common stock will not be issued. See "Note 4 — Fair Value of Financial Instruments". ________________________ (1) Excludes 563,778 and 619,235 outstanding restricted stock units that were antidilutive under the treasury stock method for the three and six months ended June 30, 2018 , respectively, and thus were not included in the above calculation. The incremental shares that could be included in the diluted EPS calculation in future periods will vary based on a variety of factors, including the future share price and the amount of unrecognized compensation cost. The incremental shares included, if any, would be less than the number of outstanding restricted stock units. (2) Excludes 1,436,970 and 1,386,443 outstanding restricted stock units that were antidilutive under the treasury stock method for the three and six months ended June 30, 2017 , respectively, and thus were not included in the above calculation. The incremental shares that could be included in the diluted EPS calculation in future periods will vary based on a variety of factors, including the future share price and the amount of unrecognized compensation cost. The incremental shares included, if any, would be less than the number of outstanding restricted stock units.

Organization (Details)

Organization (Details)	Jun. 30, 2018state
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of states in which the entity is licensed (state)	50

Summary of Significant Accoun25

Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)Segment	Jun. 30, 2017USD ($)	Jan. 01, 2018USD ($)	Dec. 31, 2017USD ($)
Significant Accounting Policies [Line Items]
Contract with customer, liability	$ 10,400		$ 10,400		$ 12,300
Client reimbursements	2,200	$ 1,000	3,400	$ 2,100
Provision for doubtful accounts	300	800	$ 300	0
Depreciation and amortization of property and equipment			Depreciation is computed using the straight-line method over the life of the assets. Amortization of leasehold improvements is computed using the straight-line method over the lesser of the life of the asset or the remaining term of the lease.
Retained earnings	(43,714)		$ (43,714)			$ (37,595)
Number of business segments | Segment			1
Minimum
Significant Accounting Policies [Line Items]
Amortization period of deferred cash retention awards			3 years
Maximum
Significant Accounting Policies [Line Items]
Amortization period of deferred cash retention awards			5 years
Revenue | Maximum
Significant Accounting Policies [Line Items]
Percent of revenues			1.00%
Aircraft
Significant Accounting Policies [Line Items]
Estimated useful lives of fixed assets (in years)			7 years
Equipment
Significant Accounting Policies [Line Items]
Estimated useful lives of fixed assets (in years)			5 years
Furniture and Fixtures
Significant Accounting Policies [Line Items]
Estimated useful lives of fixed assets (in years)			7 years
Leasehold Improvements
Significant Accounting Policies [Line Items]
Estimated useful lives of fixed assets (in years)			10 years
Estimated useful lives of fixed assets, maximum (in years)			Lesser of 10 years or the remaining lease term
Restricted Stock | Minimum
Significant Accounting Policies [Line Items]
Restricted stock units, amortization service period (years)			4 years
Restricted Stock | Maximum
Significant Accounting Policies [Line Items]
Restricted stock units, amortization service period (years)			5 years
Capital advisory engagements
Significant Accounting Policies [Line Items]
Contract with customer, liability, revenue recognized			$ 8,100
Interest income	200	$ 200	400	$ 400
ASC 606 Adjustments | Accounting Standards Update 2014-09
Significant Accounting Policies [Line Items]
Contract with customer, liability					(10,200)
Retained earnings					$ 7,600
Primary Capital Advisory Engagements
Significant Accounting Policies [Line Items]
Long term receivables related to private equity and real estate capital advisory engagements	$ 25,400		$ 25,400			$ 29,300
Installments period (in years)			3 years

Cash and Cash Equivalents (Deta

Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Restricted Cash and Cash Equivalents Items [Line Items]
Cash	$ 103,690	$ 70,459
Cash equivalents	41,769	193,315
Restricted cash - letters of credit	3,800	3,900
Total cash and cash equivalents	149,286	267,646	$ 68,022	$ 98,313
Letter of Credit
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash - letters of credit	$ 3,827	$ 3,872

Fair Value of Financial Instr27

Fair Value of Financial Instruments - Narrative (Details) - USD ($) $ in Thousands	Apr. 01, 2015	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Revenue target	$ 80,000
Contingent obligation due selling unitholders of Cogent		$ 17,354		$ 17,354		$ 13,763
Increase (decrease) in fair value contingent consideration				3,591	$ (7,513)
Cogent Partners, LP
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Maximum contingent consideration	$ 18,900
Conditional consideration (shares)	334,048
Distribution period ending on the second anniversary of the closing (years)	2 years
Distribution period ending on the fourth anniversary of the closing (years)	2 years
Contingent obligation due selling unitholders of Cogent	$ 13,100	17,400		17,400
Increase (decrease) in fair value contingent consideration		$ 2,700	$ (1,500)	$ 3,600	$ (7,500)

Fair Value of Financial Instr28

Fair Value of Financial Instruments - Assets/Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent obligation due selling unitholders of Cogent	$ 17,354	$ 13,763
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	41,769	193,315
Total assets measured at fair value on a recurring basis	41,769	193,315
Contingent obligation due selling unitholders of Cogent	17,354	13,763
Total liabilities measured at fair value on a recurring basis	17,354	13,763
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	41,769	193,315
Total assets measured at fair value on a recurring basis	41,769	193,315
Contingent obligation due selling unitholders of Cogent	0	0
Total liabilities measured at fair value on a recurring basis	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Total assets measured at fair value on a recurring basis	0	0
Contingent obligation due selling unitholders of Cogent	0	0
Total liabilities measured at fair value on a recurring basis	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Total assets measured at fair value on a recurring basis	0	0
Contingent obligation due selling unitholders of Cogent	17,354	13,763
Total liabilities measured at fair value on a recurring basis	$ 17,354	$ 13,763

Fair Value of Financial Instr29

Fair Value of Financial Instruments - Unobservable Input Reconciliation (Details) - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening Balance	$ 14,673	$ 9,090	$ 13,763	$ 15,095
Total realized and unrealized gains (losses) included in Net Income	(2,681)	1,508	(3,591)	7,513
Unrealized gains (losses) included in Other Comprehen-sive Income	0	0	0	0
Purchases	0	0	0	0
Issues	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Closing Balance	17,354	7,582	17,354	7,582
Unrealized gains (losses) for Level 3 liabilities outstanding	(2,681)	1,508	(3,591)	7,513
Contingent Consideration Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening Balance	14,673	9,090	13,763	15,095
Total realized and unrealized gains (losses) included in Net Income	(2,681)	1,508	(3,591)	7,513
Unrealized gains (losses) included in Other Comprehen-sive Income	0	0	0	0
Purchases	0	0	0	0
Issues	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Closing Balance	17,354	7,582	17,354	7,582
Unrealized gains (losses) for Level 3 liabilities outstanding	$ (2,681)	$ 1,508	$ (3,591)	$ 7,513

Fair Value of Financial Instr30

Fair Value of Financial Instruments - Quantitative Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent obligation due selling unitholders of Cogent	$ 17,354	$ 13,763
Fair Value, Measurements, Recurring
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent obligation due selling unitholders of Cogent	17,354	13,763
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent obligation due selling unitholders of Cogent	17,354	$ 13,763
Fair Value, Measurements, Recurring | Contingent Consideration Liability | Present value of expected payments | Significant Unobservable Inputs (Level 3)
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent obligation due selling unitholders of Cogent	$ 17,354
Fair Value, Measurements, Recurring | Contingent Consideration Liability | Present value of expected payments | Significant Unobservable Inputs (Level 3) | Weighted Average
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Discount Rate	11.80%

Related Parties - Additional In

Related Parties - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Related Party Transaction [Line Items]
Receivables (payables) to related parties	$ 0		$ 0		$ 0
Board of Directors Chairman
Related Party Transaction [Line Items]
Rent reimbursements	$ 100,000	$ 100,000	$ 100,000	$ 100,000

Loan Facilities - Additional In

Loan Facilities - Additional Information (Details) - USD ($)	Oct. 12, 2017	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2018	Sep. 30, 2022	Dec. 31, 2017
Line of Credit Facility [Line Items]
Secured loan payable		$ 331,451,000			$ 331,451,000				$ 339,048,000
Interest expense		5,594,000	$ 789,000		10,855,000	$ 1,608,000
Recapitalization Credit Agreement | Secured Debt
Line of Credit Facility [Line Items]
Unamortized discount (premium) and debt issuance costs, net	$ 11,500,000
Unamortized discount	1,750,000
Deferred financing costs	9,800,000
Amortization of debt issuance costs and discounts		600,000			$ 1,200,000
Long-term debt, weighted average interest rate, over time (percent)					5.55%
Recapitalization Credit Agreement | Secured Debt | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)					2.75%
Recapitalization Credit Agreement | Secured Debt | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)					3.75%
Revolving Credit Facility | Secured Debt
Line of Credit Facility [Line Items]
Covenant, leverage ratio, excess borrowings, minimum		12,500,000
Revolving Credit Facility | Recapitalization Credit Agreement | Secured Debt
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity	$ 20,000,000
Debt instrument term (years)	3 years
Secured loan payable		0			$ 0				0
Term Loan | Recapitalization Credit Agreement | Secured Debt
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity	$ 350,000,000
Debt instrument term (years)	5 years
Secured loan payable		$ 331,500,000			331,500,000				$ 339,000,000
Quarterly payment of principal					$ 8,750,000
Scenario, Forecast | Term Loan | Recapitalization Credit Agreement | Secured Debt
Line of Credit Facility [Line Items]
Quarterly payment of principal				$ 4,375,000				$ 8,750,000
Line of credit facility, annual principal payment								$ 35,000,000
Annual prepayment of principal, period of time required before year end							90 days
Annual principal payment, percentage of excess cash flow							50.00%
Prepaid, Refinanced, or Repriced Prior to April 12, 2019 | Term Loan | Recapitalization Credit Agreement | Secured Debt
Line of Credit Facility [Line Items]
Debt instrument, redemption price, percentage					101.00%
UNITED STATES | Term Loan | Secured Debt
Line of Credit Facility [Line Items]
Capital stock Of subsidiary, percentage					100.00%
Non-US | Term Loan | Secured Debt
Line of Credit Facility [Line Items]
Capital stock Of subsidiary, percentage					65.00%

Equity - Additional Information

Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Jun. 20, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Oct. 31, 2017
Stockholders Equity Note [Line Items]
Dividends declared and paid per share (usd per share)	$ 0.05	$ 0.05	$ 0.45	$ 0.10	$ 0.9
Dividend equivalents paid				$ 0.6	$ 4.1
Common Stock
Stockholders Equity Note [Line Items]
Treasury stock, value, acquired, cost method				$ 7.5	$ 12.7
Repurchased shares for award (shares)				397,580	432,121
Average repurchase price of shares for award (usd per share)				$ 18.99	$ 29.46
Restricted Stock Units
Stockholders Equity Note [Line Items]
Restricted stock units vested and issued as common stock (shares)				1,065,587	1,049,998
Common Stock | Stock Repurchase Program Authorized in September 2017 [Member]
Stockholders Equity Note [Line Items]
Stock repurchase program, authorized amount						$ 285
Treasury stock, shares, acquired (shares)				4,886,382
Treasury stock acquired, average cost per share				$ 22.87
Treasury stock, value, acquired, cost method				$ 111.8

Earnings per Share - Reconcilia

Earnings per Share - Reconciliation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Numerator for basic and diluted EPS — net income	$ 10,513	$ 6,245	$ 16,881	$ 5,499
Denominator for basic EPS — weighted average number of shares (shares)	26,992,652	31,933,830	28,545,545	32,151,409
Add — dilutive effect of:
Weighted average number of incremental shares issuable from restricted stock units (shares)	929,000	44,000	679,000	100,000
Denominator for diluted EPS — weighted average number of shares and dilutive potential shares (shares)	27,921,821	31,977,479	29,224,878	32,251,500
Earnings per share:
Basic (usd per share)	$ 0.39	$ 0.20	$ 0.59	$ 0.17
Diluted (usd per share)	$ 0.38	$ 0.20	$ 0.58	$ 0.17
Antidilutive securities excluded from EPS (shares)	563,778	1,436,970	619,235	1,386,443
Cogent Partners, LP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Incremental common shares excluded from dilutive effect of contingently issuable shares (shares)			334,048

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Excess tax benefit	$ 4.4	$ 1.5

Regulatory Requirements - Addit

Regulatory Requirements - Additional Information (Details)	6 Months Ended
	Jun. 30, 2018USD ($)
Regulatory Capital Requirements [Abstract]
Minimum net capital required	$ 5,000
Net capital	10,600,000
Excess net capital	$ 8,900,000
Aggregate indebtedness to net capital ratio (percent)	2.4
Description of minimum net capital requirements	The greater of $5,000 or 1/15 of aggregate indebtedness
Minimum net capital requirements (percent)	6.67%

Subsequent Events - Additional

Subsequent Events - Additional Information (Details)	Aug. 02, 2018$ / shares
Subsequent Event
Subsequent Event [Line Items]
Dividends declared per common share (usd per share)	$ 0.05