Greenhill & Co (GHL) 10-K 2 Mar 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 20, 2020	Jun. 30, 2019
Cover page.
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Trading Symbol	GHL
Entity Registrant Name	GREENHILL & CO INC
Entity Central Index Key	0001282977
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		18,771,782
Entity Public Float			$ 224,000,000
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-32147
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	51-0500737
Entity Address, Address Line One	300 Park Avenue
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10022
City Area Code	212
Local Phone Number	389-1500
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, par value $.01 per share
Security Exchange Name	NYSE
Documents Incorporated by Reference	Portions of the Registrant’s definitive proxy statement to be delivered to stockholders in connection with the 2019 annual meeting of stockholders to be held on April 24, 2019 are incorporated by reference in response to Part III of this Report.

Consolidated Statements of Fina

Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents ($9.8 million and $3.8 million restricted from use at December 31, 2019 and 2018, respectively)	$ 113,975	$ 156,374
Fees receivable, net of allowance for doubtful accounts of $1.1 million and $0.0 million at December 31, 2019 and 2018, respectively	77,766	61,793
Other receivables	2,519	2,595
Property and equipment, net of accumulated depreciation of $47.7 million and $45.0 million at December 31, 2019 and 2018, respectively	6,281	7,185
Operating lease right-of-use asset	28,346
Goodwill	205,992	205,922
Deferred tax asset, net	51,278	43,706
Other assets	8,218	8,125
Total assets	494,375	485,700
Liabilities and Equity
Compensation payable	26,878	56,922
Accounts payable and accrued expenses	12,412	17,167
Current income taxes payable	9,653	7,486
Operating lease obligations	30,750
Secured term loan payable	358,003	319,479
Contingent obligation due selling unitholders of Cogent	0	18,293
Deferred tax liability	12,004	3,990
Total liabilities	449,700	423,337
Common stock, par value $0.01 per share; 100,000,000 shares authorized, 46,801,812 and 45,001,788 shares issued as of December 31, 2019 and 2018, respectively; 18,355,907 and 20,404,996 shares outstanding as of December 31, 2019 and 2018, respectively	468	450
Restricted stock units	77,657	71,596
Additional paid-in capital	887,095	846,721
Exchangeable shares of subsidiary; 257,156 shares issued as of December 31, 2019 and 2018; 0 and 32,804 shares outstanding as of December 31, 2019 and 2018, respectively	0	1,958
Retained earnings	69,093	63,427
Accumulated other comprehensive income (loss)	(34,115)	(35,705)
Treasury stock, at cost, par value $0.01 per share; 28,445,905 and 24,596,792 shares as of December 31, 2019 and 2018, respectively	(955,523)	(886,084)
Stockholders’ equity	44,675	62,363
Total liabilities and equity	$ 494,375	$ 485,700

Consolidated Statements of Fi_2

Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Restricted cash - letters of credit	$ 9,800	$ 3,800
Advisory fees, allowance for credit loss	1,100	0
Accumulated depreciation and amortization	$ 47,735	$ 45,032
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)	46,801,812	45,001,788
Common stock, shares outstanding (shares)	18,355,907	20,404,996
Exchangeable shares of subsidiary, shares issued (shares)	257,156	257,156
Exchangeable shares of subsidiary, shares outstanding (shares)	0	32,804
Treasury stock, par value (usd per share)	$ 0.01	$ 0.01
Treasury stock, shares (shares)	28,445,905	24,596,792

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues
Revenues	$ 301,012	$ 351,985	$ 239,182
Operating Expenses
Employee compensation and benefits	178,946	195,195	160,201
Occupancy and equipment rental	22,289	21,933	20,713
Depreciation and amortization	2,565	2,870	3,114
Information services	9,940	9,898	9,529
Professional fees	10,017	10,465	8,212
Travel related expenses	13,523	13,483	13,142
Other operating expenses	17,889	17,273	17,371
Total operating expenses	255,169	271,117	232,282
Total operating income	45,843	80,868	6,900
Interest expense	27,420	22,438	7,198
Income (loss) before taxes	18,423	58,430	(298)
Provision for taxes	7,445	19,208	26,353
Net income (loss)	$ 10,978	$ 39,222	$ (26,651)
Average shares outstanding:
Basic (shares)	24,024,674	26,813,285	32,074,894
Diluted (shares)	24,272,479	27,637,720	32,074,894
Earnings (loss) per share:
Basic (usd per share)	$ 0.46	$ 1.46	$ (0.83)
Diluted (usd per share)	$ 0.45	$ 1.42	$ (0.83)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Consolidated net income (loss)	$ 10,978	$ 39,222	$ (26,651)
Currency translation adjustment, net of tax	1,590	(13,483)	10,176
Comprehensive income (loss)	$ 12,568	$ 25,739	$ (16,475)

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Restricted stock units	Common stock	Restricted stock unitsRestricted stock units	Additional paid-in capital	Exchangeable shares of subsidiary	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock	Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of the change in accounting principle related to revenue recognition | Accounting Standards Update 2014-09							$ 0
Retained earnings, beginning of the period, as adjusted							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]
Common stock issued			24		65,231
Restricted stock units recognized, net of forfeitures				40,597
Restricted stock units delivered				(45,992)
Tax effect of issuance of contingent equity earnout					0
Tax benefit from the delivery of restricted stock units					847
Exchangeable shares of subsidiary delivered						0
Dividends							(47,552)
Net income (loss)	$ (26,651)						(26,651)
Currency translation adjustment, net of tax	10,176							10,176
Repurchased									(79,561)
Ending Balance at Dec. 31, 2017			438	80,512	800,806	1,958	37,595	(22,222)	(690,785)	$ 208,302
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of the change in accounting principle related to revenue recognition | Accounting Standards Update 2014-09							(7,645)
Retained earnings, beginning of the period, as adjusted							29,950
Common stock issued			12		45,915
Restricted stock units recognized, net of forfeitures				37,941
Restricted stock units delivered				(46,857)
Tax effect of issuance of contingent equity earnout					0
Tax benefit from the delivery of restricted stock units					0
Exchangeable shares of subsidiary delivered						0
Dividends							(5,745)
Net income (loss)	39,222						39,222
Currency translation adjustment, net of tax	(13,483)							(13,483)
Repurchased		$ (8,700)							(195,299)
Ending Balance at Dec. 31, 2018	62,363		450	71,596	846,721	1,958	63,427	(35,705)	(886,084)	62,363
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of the change in accounting principle related to revenue recognition | Accounting Standards Update 2014-09							0
Retained earnings, beginning of the period, as adjusted							63,427
Common stock issued			18		41,582
Restricted stock units recognized, net of forfeitures				46,382
Restricted stock units delivered				(40,321)
Tax effect of issuance of contingent equity earnout					(1,208)
Tax benefit from the delivery of restricted stock units					0
Exchangeable shares of subsidiary delivered						(1,958)
Dividends							(5,312)
Net income (loss)	10,978						10,978
Currency translation adjustment, net of tax	1,590							1,590
Repurchased		$ (14,000)							(69,439)
Ending Balance at Dec. 31, 2019	$ 44,675		$ 468	$ 77,657	$ 887,095	$ 0	$ 69,093	$ (34,115)	$ (955,523)	$ 44,675

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Equity (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 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	$ 0.01
Treasury stock
Treasury stock, par value (usd per share)	$ 0.01	$ 0.01	$ 0.01

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities:
Net income (loss)	$ 10,978	$ 39,222	$ (26,651)
Non-cash items included in net income (loss):
Depreciation and amortization	4,487	5,175	3,114
Net investment (gains) losses	(113)	210	258
Restricted stock units recognized, net	46,382	37,941	40,597
Allowance for doubtful accounts	1,197	0	0
Deferred taxes, net	(815)	5,435	14,594
Loss (gain) on fair value of contingent obligation	575	4,531	(1,332)
Non-cash portion of loss on refinancing	1,759	0	0
Loss (gain) on sales of property and equipment	0	(777)	0
Changes in operating assets and liabilities:
Fees receivable	(17,170)	2,451	3,896
Other receivables and assets	(143)	(836)	449
Payment of contingent obligation due selling unitholders of Cogent	(5,724)	0	0
Compensation payable	(30,939)	30,313	(11,505)
Accounts payable and accrued expenses	1,690	(9,546)	5,409
Current income taxes payable	2,168	2,175	(13,657)
Net cash provided by operating activities	14,332	116,294	15,172
Investing activities:
Distributions from investments, net	239	149	221
Purchases of property and equipment	(1,648)	(2,124)	(2,555)
Sales of property and equipment	0	1,357	0
Net cash used in investing activities	(1,409)	(618)	(2,334)
Financing activities:
Payment of contingent obligation due selling unitholders of Cogent	(13,144)	0	0
Proceeds from revolving bank loan	0	0	69,355
Repayment of revolving bank loan	0	0	(133,425)
Repayment of bank term loans	0	0	(16,875)
Proceeds from secured term loan, net	48,248	0	339,048
Repayment of secured term loan	(18,125)	(21,875)	0
Proceeds from the issuance of common stock	0	0	20,000
Dividends paid	(4,417)	(5,158)	(47,552)
Purchase of treasury stock	(69,439)	(195,299)	(79,561)
Net cash provided by (used in) financing activities	(56,877)	(222,332)	150,990
Effect of exchange rate changes	1,555	(4,616)	5,505
Net increase (decrease) in cash and cash equivalents	(42,399)	(111,272)	169,333
Cash and cash equivalents, beginning of year	156,374	267,646	98,313
Cash and cash equivalents, end of year	113,975	156,374	267,646
Supplemental disclosure of cash flow information:
Cash paid for interest	21,511	20,945	6,567
Cash paid for taxes, net of refunds	$ 6,201	$ 10,299	$ 26,026

Organization

Organization	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Note 1 — 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. The Company acts for clients located throughout the world from our global offices in the United States, Australia, Brazil, Canada, Germany, Hong Kong, Japan, Singapore, 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”) and Greenhill & Co. Australia Pty Limited (“Greenhill Australia”). 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”). 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	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2 — Summary of Significant Accounting Policies Basis of Financial Information These 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 compensation accruals and other matters. Management believes that the estimates used in preparing its 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 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. Revenue Recognition Subsequent to the adoption of ASC 606 The Company adopted ASU 2014-09, Revenue from Contracts with Customers, (codified in ASC 606) on January 1, 2018. 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 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 revenues for financing advisory and restructuring engagements as the services are provided to the client, based on the 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, deferred revenue (also known as contract liabilities) was $3.9 million, $5.6 million and $12.3 million as of December 31, 2019, December 31, 2018 and January 1, 2018, respectively. Deferred revenue is included in accounts payable and accrued expenses in the consolidated statements of financial condition. During the years ended December 31, 2019 and 2018, the Company recognized $4.7 million and $9.3 million of revenues, respectively, that were included in the deferred revenue (contract liabilities) balance at the beginning of each respective period. The Company’s clients reimburse certain expenses incurred by the Company in the conduct of advisory engagements. Client reimbursements totaled $6.4 million, $7.0 million and $4.7 million for the years ended December 31, 2019, 2018, and 2017, respectively. Such reimbursements were reported as revenues and operating expenses for the years ended December 31, 2019 and 2018, and as a reduction to operating expenses for the year ended December 31, 2017, as discussed below, with no impact to operating income in the periods presented. Prior to the adoption of ASC 606 Prior to January 1, 2018, it was the Company’s accounting policy to recognize revenue when (i) there was persuasive evidence of an arrangement with a client, (ii) the agreed-upon services had been completed and delivered to the client or the transaction or events noted in the engagement letter were determined to be substantially complete, (iii) fees were fixed and determinable, and (iv) collection was reasonably assured. The Company recognized revenues for mergers and acquisitions or financing advisory and restructuring engagements when the services related to the underlying transactions were completed in accordance with the terms of the engagement letter and all other requirements for revenue recognition were satisfied. The Company recognized capital advisory fees from primary capital raising transactions at the time of the client’s acceptance of capital or capital commitments to a fund in accordance with the terms of the engagement letter. Generally, fee revenue was determined based upon a fixed percentage of capital committed to the fund. For multiple closings, revenue was recognized at each interim closing based on the amount of capital committed at each closing at the fixed fee percentage. At the final closing, revenue was recognized at the fixed percentage for the amount of capital committed since the last interim closing. The Company recognized capital advisory fees from secondary market transactions at the time the sale or transfer of the capital interest was completed in accordance with the terms of the engagement letter. Generally, fee revenue was determined based upon a fixed percentage of the transaction value. While the majority of the Company’s fee revenue was earned at the conclusion of a transaction or closing of a fund, on-going retainer fees, substantially all of which relate to non-success based strategic advisory and financing advisory and restructuring assignments, were also earned and recognized as revenue over the period in which the related service was rendered. 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 an original maturity date of three months or less, when purchased, to be cash equivalents. Cash equivalents primarily consist of money market funds and other short-term highly liquid investments with original maturities of three months or less 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”. 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 bad debt expense of $1.2 million, $0.3 million and $1.1 million for the years ended December 31, 2019, 2018 and 2017, respectively. Included in the fees receivable balances at December 31, 2019 and 2018 were $10.5 million and $20.0 million, respectively, of long term receivables related to primary capital advisory engagements, which are generally paid in installments over a period of three years. Credit risk related to 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. See “Note 5 — Goodwill”. 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 consolidated statements of changes in stockholders’ equity. Compensation Payable Included in compensation payable are discretionary compensation awards comprised of annual cash bonuses and long-term incentive compensation, consisting of deferred cash retention awards, which are non-interest bearing, and generally amortized ratably over a three five Restricted Stock Units The Company accounts for its share-based compensation payments by recording the fair value of restricted stock units (RSUs) granted to employees as compensation expense. The restricted stock units are generally amortized ratably over a three five 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 10 — 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 stock 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 11 — 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 consolidated statements of changes in stockholders’ equity. Foreign currency transaction gains and losses are included in the 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 7 — Fair Value of Financial Instruments”. Leases The Company leases office space for its operations around the globe. Certain leases include options to renew, which can be exercised at the Company’s sole discretion. The Company determines if a contract contains a lease at contract inception. Operating lease assets represent the Company’s right to use the underlying asset and operating lease liabilities represent the Company’s obligation to make lease payments. Operating lease assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. When determining the lease term, the Company generally does not include options to renew as it is not reasonably certain at contract inception that the Company will exercise the option(s). The Company uses the implicit rate when readily determinable and its incremental borrowing rate when the implicit rate is not readily determinable. The Company’s incremental borrowing rate is determined using its secured borrowing rate and giving consideration to the currency and term of the associated lease as appropriate. The lease payments used to determine the Company’s operating lease assets may include lease incentives, stated rent increases and escalation clauses linked to rates of inflation when determinable and are recognized in operating lease assets in the condensed consolidated balance sheets. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. The straight-lining of rent expense results in differences in the operating lease right-of-use asset and operating lease obligations on the consolidated statement of financial position. 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: 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. Recently Adopted Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases (“ASU 2016-02”), which requires the recognition of lease assets and lease liabilities for operating leases, among other changes. The Company adopted this standard on January 1, 2019 utilizing a modified retrospective approach. The Company elected to apply practical expedients provided in the standard that allowed the Company to not reassess whether expired or existing contracts are or contain leases, not reassess lease classification for expired or existing leases (e.g., pre-existing operating leases are classified as operating leases under the new standard), and not reassess initial direct costs for existing leases. The impact of adopting ASU 2016-02 was an increase of $38.1 million to the Company’s assets and liabilities for the operating lease right-of-use assets and operating lease obligations on the condensed consolidated statement of financial condition as of January 1, 2019. Upon adoption, the Company also reclassified $3.2 million of deferred rent from accounts payable and accrued expenses to operating lease obligations on the condensed consolidated statement of financial condition. Differences in the operating lease right-of-use asset and operating lease obligations are due to straight-lining rent expense and the resulting deferred rent. There was no net impact to the condensed consolidated statement of operations. 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 June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326) - Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). This ASU changes how companies measure credit losses on most financial instruments, including accounts receivable. Companies will be required to estimate lifetime expected credit losses, which is generally expected to result in earlier recognition of credit losses. The Company adopted this standard effective on January 1, 2020 under a modified retrospective approach. The Company estimates that as of January 1, 2020, the impact of adoption will decrease the Company’s assets and retained earnings by approximately $0.2 million.

Cash and Cash Equivalents

Cash and Cash Equivalents	12 Months Ended
	Dec. 31, 2019
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents	Note 3 — Cash and Cash Equivalents The carrying values of the Company’s cash and cash equivalents are as follows: As of December 31, 2019 2018 (in thousands) Cash $ 59,455 $ 80,400 Cash equivalents 44,751 72,193 Restricted cash - letters of credit 9,769 3,781 Total cash and cash equivalents $ 113,975 $ 156,374 In June 2019, the Company delivered a security deposit in the form of a $5.9 million standby letter of credit to the landlord of a new office lease. Under certain circumstances, the Company will be entitled to periodically reduce the amount of the letter of credit amount down ultimately to approximately $3.5 million from and after the fifth anniversary of the rent commencement. See “Note 16 — Leases”. The carrying value of the Company’s cash equivalents approximates fair value. See “Note 7 — Fair Value of Financial Instruments”. Letters of credit were secured by cash held on deposit. See “Note 14 — Commitments and Contingencies”.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property and Equipment	Note 4 — Property and Equipment Property and equipment consist of the following: As of December 31, 2019 2018 (in thousands) Equipment $ 22,452 $ 21,451 Furniture and fixtures 7,758 7,684 Leasehold improvements 23,806 23,082 54,016 52,217 Less accumulated depreciation and amortization (47,735) (45,032) Total property and equipment, net $ 6,281 $ 7,185

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Note 5 — Goodwill Goodwill consists of the following: As of December 31, 2019 2018 (in thousands) Balance, January 1 $ 205,922 $ 217,737 Foreign currency translation adjustments 70 (11,815) Balance, December 31 $ 205,992 $ 205,922

Other Assets

Other Assets	12 Months Ended
	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	Note 6 — Other Assets Other assets consist of the following: As of December 31, 2019 2018 (in thousands) Prepaid expenses and other assets $ 6,098 $ 5,993 Rent deposits 1,856 1,764 Other tangible assets 264 368 Total other assets $ 8,218 $ 8,125

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Note 7 — Fair Value of Financial Instruments Assets Measured at Fair Value on a Recurring Basis Assets and liabilities are classified in their entirety based on their lowest level of input that is significant to the fair value measurement. As of December 31, 2019, the Company had Level 1 assets measured at fair value. As of December 31, 2018, the Company had Level 1 assets and Level 2 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 December 31, 2019 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, 2019 (in thousands) Assets Cash equivalents $ 44,751 $ — $ — $ 44,751 Total $ 44,751 $ — $ — $ 44,751 Assets Measured at Fair Value on a Recurring Basis as of December 31, 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 December 31, 2018 (in thousands) Assets Cash equivalents $ 72,193 $ — $ — $ 72,193 Total $ 72,193 $ — $ — $ 72,193 Liabilities Measured at Fair Value on a Recurring Basis 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 were to be made if secondary capital advisory revenues of $80.0 million or more were earned during either the two two two two 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 prior to its settlement in April 2019. The liability arose as a result of the acquisition of Cogent and was categorized as a Level 3 liability. Through March 31, 2019, the liability was remeasured each quarter based on the probability of achieving the target revenue threshold and weighted average discount rate as discussed below. In the third quarter of 2018, the liability was transferred to Level 2 as the only remaining fair value input was the present value discount. Liabilities Measured at Fair Value on a Recurring Basis as of December 31, 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 December 31, 2018 (in thousands) Liabilities Contingent obligation due selling unitholders of Cogent $ — $ 18,293 $ — $ 18,293 Total $ — $ 18,293 $ — $ 18,293 Changes in Level 3 liabilities measured at fair value on a recurring basis for the year ended December 31, 2018 Opening Balance as of January 1, 2018 Total realized and unrealized gains (losses) included in Net Income Unrealized gains (losses) included in Other Comprehensive Income Purchases Issues Sales Transfers Out Closing Balance as of December 31, 2018 Unrealized gains (losses) for Level 3 liabilities outstanding at December 31, 2018 (in thousands) Liabilities Contingent obligation due selling unitholders of Cogent $ 13,763 $ (4,021) $ — $ — $ — $ — $ (17,784) $ — $ — Total $ 13,763 $ (4,021) $ — $ — $ — $ — $ (17,784) $ — $ — Changes in Level 3 liabilities measured at fair value on a recurring basis for the year ended December 31, 2017 Opening Balance as of January 1, 2017 Total realized and unrealized gains (losses) included in Net Income Unrealized gains (losses) included in Other Comprehensive Income Purchases Issues Sales Transfers Out Closing Balance as of December 31, 2017 Unrealized gains (losses) for Level 3 liabilities outstanding at December 31, 2017 (in thousands) Liabilities Contingent obligation due selling unitholders of Cogent $ 15,095 $ 1,332 $ — $ — $ — $ — $ — $ 13,763 $ 1,332 Total $ 15,095 $ 1,332 $ — $ — $ — $ — $ — $ 13,763 $ 1,332 Realized and unrealized gains (losses) are reported as a component of other operating expenses in the consolidated statements of operations. There were no Level 3 liabilities at December 31, 2019 or 2018. 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	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Related Parties	Note 8 — Related Parties At December 31, 2019 and 2018, the Company had no amounts receivable from or payable to related parties. Prior to June 2018, the Company subleased airplane and office space to a firm owned by the then Chairman of the Company. The Company recognized rent reimbursements of less than $0.1 million for each of the years ended December 31, 2018 and 2017. During 2018 and 2017, the Company paid less than $0.1 million each year for the use of an aircraft owned by the Chairman of the Company.

Loan Facilities

Loan Facilities	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Loan Facilities	Note 9 — Loan Facilities In October 2017, as part of a recapitalization plan, the Company entered into a credit agreement with a syndicate of lenders, who lent a face amount of $350.0 million under a five three On April 12, 2019, the Company refinanced its 2017 Term Loan Facility with borrowings of $375.0 million from a new five As of December 31, 2019 2018 (in thousands) Term Loan Facility carrying value $ 358,003 $ 319,479 Unamortized discount 2,365 1,313 Unamortized debt issuance costs 5,257 7,333 Total Term Loan Facility 365,625 328,125 Current maturities of Term Loan Facility (18,750) (35,000) Total long-term debt $ 346,875 $ 293,125 Effective with the refinancing in April 2019, borrowings under the Term Loan Facility bear interest at either the U.S. Prime Rate plus 2.25% or LIBOR plus 3.25%, which represents a 50 basis point reduction from the applicable borrowing rates of the 2017 Term Loan Facility. Borrowings under the Term Loan Facility and 2017 Term Loan Facility had a weighted average interest rate for the years ended December 31, 2019 and 2018 of 5.7% and 5.8%, respectively (with the borrowing rate ranging from 5.0% to 6.6% and from 5.1% to 6.6%, respectively). The Term Loan Facility requires quarterly principal amortization payments of $4.7 million (or $18.8 million annually), from September 30, 2019 through March 31, 2024, with the remaining outstanding balance due at maturity on April 12, 2024. In addition, beginning for the year ended December 31, 2019, the Company may be required to make annual repayments of principal on the Term Loan Facility within ninety days of year-end of up to 50% of its annual excess cash flow as defined in the credit agreement based on a calculation of net leverage. For each of the years ended December 31, 2019 and 2018, based upon the Company’s financial results, an excess cash flow payment was not required. 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. The Revolving Loan Facility was not refinanced and the amount, interest rate and maturity remained unchanged from the original terms. There have been no borrowings under the Revolving Loan Facility. 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, 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 December 31, 2019 and 2018, the Company was compliant with all loan covenants. In conjunction with the refinancing of the 2017 Term Loan Facility in April 2019, the Company incurred fees of $5.7 million, of which $2.7 million was recorded as deferred financing costs and $3.0 million was expensed. In addition, as a result of the refinancing, $1.8 million of previously deferred fees, or fees in aggregate of $4.8 million, were charged to expense and recorded as interest expense in the consolidated statements of operations. The deferred financing costs incurred in connection with the refinancing, along with the remaining unamortized costs from the 2017 Term Loan Facility which, as of April 2019, were $9.0 million, are being amortized into interest expense over the remaining life of the obligation and recorded as a reduction in the carrying value of the Term Loan Facility in the consolidated statement of financial condition. For the years ended December 31, 2019 and 2018, in addition to the charge related to the refinancing in 2019, the Company incurred incremental interest expense of $1.9 million and $2.3 million, respectively, related to the amortization of these costs. As of December 31, 2019, the carrying value of the Term Loan Facility, excluding the unamortized debt issuance costs and discount that are presented as a reduction to the debt principal balance, approximated the fair value. As the borrowing is not accounted for at fair value, the fair value is not included in the Company’s fair value hierarchy in “Note 7 — Fair Value of Financial Instruments,” however, had the borrowing been included, it would have been classified in Level 2. During the year ended December 31, 2019, the Company made mandatory principal payments on the 2017 Term Loan Facility of $8.8 million and on the Term Loan Facility of $9.4 million, or $18.1 million in total. All mandatory repayments of

Equity

Equity	12 Months Ended
	Dec. 31, 2019
Stockholders' Equity Note [Abstract]
Equity	Note 10 — Equity In September 2017, the Company announced plans for a leveraged recapitalization, which included the authorization to repurchase up to $285 million of the Company’s common stock. As part of the refinancing in April 2019, the amount permitted and authorized for future share repurchases was increased to $339.1 million, or by $75.0 million from the amount repurchased in advance of the refinancing. During the year ended December 31, 2019, the Company repurchased 3,275,641 shares of common stock through open market transactions at an average price of $16.93 per share, for a total cost of $55.5 million. During the year ended December 31, 2018, the Company repurchased 7,497,635 shares of common stock through a modified Dutch auction tender and open market transactions at an average price of $24.89 per share, for a total cost of $186.6 million. During the year ended December 31, 2017, the Company repurchased 3,777,548 shares of common stock through a tender offer and other open market transactions at an average price of $17.41 per share, for a total cost of $65.8 million. In addition, the Company incurred fees and expenses relating to tender offers of $0.2 million and $0.7 million during the years ended December 31, 2018 and 2017, respectively. As of December 31, 2019, the Company has repurchased under the recapitalization plan 14,550,824 shares of common stock at an average price of $21.16 per share for a total cost of $307.9 million and had $31.2 million remaining and authorized under its repurchase plan. In November 2017, the Company's then Chairman, through an entity controlled by him, and the Company's now Chairman and Chief Executive Officer, in his personal capacity and through an entity controlled by him, each purchased $10.0 million of the Company’s common stock, for an aggregate total of $20.0 million, and a total of 1,159,420 common shares were issued. In connection with the acquisition of Cogent, the Company issued 779,454 shares of common stock on the acquisition date, April 1, 2015. In addition, the Company issued 334,048 shares of common stock shortly after the revenue target for the second two year period ended March 31, 2019 was achieved. The fair value of the contingent issuance of common shares was valued on the date of the acquisition at $11.9 million and was recorded as additional paid in capital in the consolidated statements of financial condition. Upon delivery of the shares in April 2019, the par value of the shares was transferred to common stock in the consolidated statement of financial condition. In addition, $1.2 million was reflected as an adjustment to additional paid-in capital in the consolidated statement of financial condition for the tax effect of the difference in the acquisition date value of the contingently issuable shares and the fair value of the shares when issued in April 2019. See “Note 7 — Fair Value of Financial Instruments” and “Note 11 — Earnings per Share”. During 2019, 1,407,095 restricted stock units vested and were settled in shares of common stock, of which the Company is deemed to have repurchased 573,472 shares at an average price of $24.37 per share for a total cost of $14.0 million in conjunction with the payment of tax liabilities in respect of stock delivered to its employees in settlement of restricted stock units. During 2018, 1,238,733 restricted stock units vested and were settled in shares of common stock, of which the Company is deemed to have repurchased 433,507 shares at an average price of $20.00 per share for a total cost of $8.7 million in conjunction with the payment of tax liabilities in respect of stock delivered to its employees in settlement of restricted stock units. Dividends declared and paid on outstanding common share were $0.20, $0.20 and $1.40 for each of the years ended December 31, 2019, 2018 and 2017, respectively. In addition, dividend equivalent amounts are accrued and paid on outstanding restricted stock units and amounted to $1.3 million, $1.1 million and $6.3 million for the years ended December 31, 2019, 2018 and 2017, respectively, and paid amounts are included in dividends paid on the consolidated statements of cash flows. In the event a restricted stock unit holder’s employment is terminated, to the extent dividends have been paid to the holder, a portion of the dividend equivalent amount is required to be paid back (a “clawback”) to the Company and is netted against the dividend equivalent amounts herein. See “Note 13 — Deferred Compensation — Restricted Stock Units”.

Earnings per Share

Earnings per Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Earnings per Share	Note 11 — Earnings per Share The computations of basic and diluted EPS are set forth below: For the Years Ended December 31, 2019 2018 2017 (in thousands, except per share amounts) Numerator for basic and diluted EPS — net income (loss) $ 10,978 $ 39,222 $ (26,651) Denominator for basic EPS — weighted average number of shares 24,025 26,813 32,075 Add — dilutive effect of: Restricted stock units and Cogent Earnout shares 247 (1) 825 (1) — (1) Denominator for diluted EPS — weighted average number of shares and dilutive securities 24,272 27,638 32,075 Earnings (loss) per share: Basic EPS $ 0.46 $ 1.46 $ (0.83) Diluted EPS $ 0.45 $ 1.42 $ (0.83) For the year ended December 31, 2018, the weighted average number of shares and dilutive potential shares included 334,048 shares of common stock that were to be issued to certain selling unitholders of Cogent in April 2019 as the revenue target related to the Earnout was achieved during the quarter ended September 30, 2018. See “Note 7 — Fair Value of Financial Instruments”. ________________________

Retirement Plan

Retirement Plan	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
Retirement Plan	Note 12 — Retirement Plan The Company sponsors qualified defined contribution plans in certain jurisdictions. Qualified plans comply with applicable local laws and regulations. The Company incurred costs of $1.0 million, $1.3 million and $1.6 million for contributions to the retirement plans for the years ended December 31, 2019, 2018 and 2017, respectively. There was $0.1 million related to contributions due to the Retirement Plans included in compensation payable on the consolidated statements of financial condition at both December 31, 2019 and 2018.

Deferred Compensation

Deferred Compensation	12 Months Ended
	Dec. 31, 2018
Share-based Payment Arrangement [Abstract]
Deferred Compensation	Note 13 — Deferred Compensation Restricted Stock Units The Company has an equity incentive plan to motivate its employees and allow them to participate in the ownership of its stock. Under the Company’s plan, restricted stock units, which represent a right to a future payment equal to one share of common stock, may be awarded to employees, directors and certain other non-employees as selected by the Compensation Committee. Awards granted under the plan are generally amortized ratably over a three five The activity related to the restricted stock units is set forth below: Restricted Stock Units Outstanding 2019 2018 Units Grant Date Weighted Average Fair Value Units Grant Date Weighted Average Fair Value Outstanding, January 1, 6,210,282 $ 22.73 5,396,728 $ 28.02 Granted 2,294,967 22.55 2,741,343 18.94 Delivered (1,468,700) 27.58 (1,265,500) 36.63 Forfeited (255,074) 22.84 (662,289) 23.49 Outstanding, December 31, 6,781,475 $ 21.60 6,210,282 $ 22.73 For the years ended December 31, 2019, 2018 and 2017, the Company recognized compensation expense from the amortization of restricted stock units, net of forfeitures, of $45.8 million, $38.4 million and $40.2 million, respectively. The weighted-average grant date fair value for restricted stock units granted during the years ended December 31, 2019, 2018 and 2017 was $22.55, $18.94 and $20.87, respectively. As of December 31, 2019, unrecognized restricted stock units compensation expense was $58.4 million, with such unrecognized compensation expense expected to be recognized over a weighted average period of approximately 1.7 years. The Company awards restricted stock units to employees under the equity incentive plan, primarily in connection with its annual bonus awards and compensation agreements for new hires. In certain jurisdictions, the Company may settle share-based payment awards in cash in lieu of shares of common stock to obtain tax deductibility. In these circumstances, the awards are settled in the cash equivalent value of the Company’s shares of common stock based upon their value at settlement date. These cash-settled share-based awards are remeasured at fair value at each reporting period. The Company also awards performance-based restricted stock units (“PRSU”), as part of long-term incentive compensation to a limited number of key employees. The actual performance relative to target performance is measured quarterly and the probability-weighted likelihood of achievement is recorded. Deferred Cash Compensation As part of its long-term incentive award program, the Company grants deferred cash retention awards to certain eligible employees. The deferred awards, which generally vest ratably over a three five For the years ended December 31, 2019, 2018 and 2017, the Company recognized compensation expense from the amortization of deferred cash compensation, net of estimated forfeitures, of $8.9 million, $7.7 million and $13.1 million, respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 14 — Commitments and Contingencies Diversified financial institutions in certain jurisdictions in which we operate issued six and five letters of credit on behalf of the Company to secure office space leases, which totaled $9.8 million and $3.8 million at December 31, 2019 and 2018, respectively. These letters of credit were secured by cash held on deposit. At December 31, 2019 and 2018, no amounts had been drawn under any of the letters of credit. See “Note 3 — Cash and Cash Equivalents”. The Company leases office space for its operations around the globe. See “Note 16 — Leases”. The Company is from time to time involved in legal proceedings incidental to the ordinary course of its business. The Company does not believe any such proceedings will have a material adverse effect on its results of operations.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Note 15 — Income Taxes The Company is subject to U.S. federal, state and local, as well as foreign, corporate income taxes. The components of the provision for income taxes reflected on the consolidated statements of operations are set forth below: For the Years Ended December 31, 2019 2018 2017 (in thousands) Current taxes: U.S. federal $ 2,868 $ 1,868 $ 8,792 State and local 410 1,937 1,181 Foreign 4,982 9,968 1,786 Total current tax expense 8,260 13,773 11,759 Deferred taxes: U.S. federal 293 202 14,626 State and local (534) 50 795 Foreign (574) 5,183 (827) Total deferred tax (benefit) expense (815) 5,435 14,594 Total tax expense $ 7,445 $ 19,208 $ 26,353 The Company accounts for income taxes in accordance with ASC 740, which requires an asset and liability approach for financial accounting and reporting for income taxes. Deferred taxes are provided for the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts for income tax purposes. These deferred taxes are measured using the enacted tax rates and laws that will be in effect when such differences are expected to reverse. Changes in tax laws and accounting pronouncements enacted in the year ended December 31, 2017 significantly affected the Company’s income tax provision in subsequent years. Effective in 2017, the Company was subject to a new accounting pronouncement which required it to record a charge or benefit in its income tax provision for the tax effect of the difference between the grant price fair value of RSUs and the fair value of such awards at the time of vesting in addition to the income tax benefit for the tax effect of dividend payments on restricted stock units. On December 22, 2017, the Tax Cuts and Jobs Act (the “TCJA”) was enacted making 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, imposing a one-time repatriation tax in the current year for the deemed repatriation of earnings of foreign subsidiaries previously tax deferred before the effective date of the legislation, and implementing a territorial-type tax system with a minimum tax for certain foreign earnings starting in 2018. Although the reduction in the corporate income tax rate was not effective until after the year ended December 31, 2017, the legislation required the Company to revalue its deferred tax assets and liabilities and charge to deferred tax expense the future impact of the lower corporate tax rate as of the effective date of the legislation. In accordance with ASC 740, this revaluation adjustment included the tax effect related to the change in corporate tax rates for foreign currency translation adjustments that had previously been accounted for as a tax adjustment in other comprehensive income in the consolidated statements of changes in stockholders’ equity. The effect of the revaluation of the Company’s deferred tax assets and liabilities resulted in a net charge of $15.4 million for the year ended December 31, 2017. Despite having significant tax deferred foreign earnings at the effective date of the legislation, the one-time repatriation tax charge for previously deferred earnings of foreign subsidiaries did not result in a charge in the tax provision for the year ended December 31, 2017, because the calculation of the deemed repatriation allows the offset of cumulative foreign earning by jurisdiction against cumulative foreign losses of other jurisdictions. The impact of the implementation of this territorial-type tax system did not have a significant impact in the income tax provisions for the tax years ended December 31, 2019 and is not expected to have a material impact in future years. As such, in order to better align its structure and operations with these new tax laws, the Company no longer intends to indefinitely reinvest its non-U.S. subsidiary earnings outside of the United States. In addition, the TCJA eliminated the performance award exception related to executive compensation, making certain compensation paid to covered employees non-deductible in current and future periods. Effective in 2019, the Company adopted ASU No. 2016-02, Leases, requiring the recognition of lease assets and liabilities for operating leases. As part of the adoption of this new accounting standard, temporary differences are recognized for tax purposes and reflected separately in the balance sheet as deferred lease assets and lease liabilities. Significant components of the Company’s net deferred tax assets and liabilities are set forth below: As of December 31, 2019 2018 (in thousands) Deferred tax assets: Compensation and benefits $ 21,706 $ 19,353 Depreciation and amortization 1,816 1,539 Cumulative translation adjustment 12,235 12,624 Operating loss carryforwards 4,644 5,256 Capital loss carryforwards 1,874 1,909 Lease asset 7,652 — Other financial accruals 3,760 5,488 Valuation allowances (2,409) (2,463) Total deferred tax assets 51,278 43,706 Deferred tax liabilities: Lease liability 6,959 — Other financial accruals 5,045 3,990 Total deferred tax liabilities 12,004 3,990 Net deferred tax asset $ 39,274 $ 39,716 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. The Company’s deferred taxes for operating loss carryforwards relate to losses incurred in foreign jurisdictions. These jurisdictions had been profitable in prior years and the Company believes it is more likely than not they will be profitable in future years. However, management has carefully considered the need for a valuation allowance by evaluating each foreign jurisdiction separately and considering items such as historical and estimated future taxable income, cost bases, and other various factors. Based on all available information, the Company has determined that it is more likely than not that it will realize the full benefit of these operating loss carryforwards and other deferred tax assets in the majority of its foreign jurisdictions notwithstanding a nominal reserve of $0.5 million due to local tax rules. At December 31, 2019, the Company had foreign operating loss carryforwards, which in aggregate totaled $14.7 million, including the reserved amount. These operating loss carryforwards may be carried forward for six years and longer. In addition to the valuation allowances against certain foreign operating loss carryforwards, the Company has previously recorded a valuation allowance against a deferred tax asset related to a capital loss carryforward in the United Kingdom. This capital loss was realized from the sale of an investment in the United Kingdom and can be carried forward indefinitely but can only be utilized against capital gain in the same jurisdiction. Since the Company has nominal remaining investments in the United Kingdom and considers it more likely than not that the Company will not generate a capital gain in the United Kingdom, the Company had previously established a full valuation allowance against this related deferred tax asset. As of December 31, 2019, the amount of the deferred tax asset and corresponding valuation allowance for the capital loss carryforward in the United Kingdom remained unchanged from the prior year and is $1.9 million. 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 December 31, 2019, the Company does not expect any material changes in its tax provision related to any current or future audits. The Company recognizes tax positions in the financial statements only when management believes it is more likely than not that the position will be sustained on examination by the relevant taxing authority based on the technical merits of the position. A position that meets this standard is measured at the largest amount of benefit that will more likely than not be realized on settlement. A liability is established for differences between positions taken in a tax return and amounts recognized in the financial statements. The Company performed an analysis of its tax positions as of December 31, 2019, and determined that there was no requirement to accrue any material additional liabilities. Also, when present as part of the tax provision calculation, interest and penalties have been reported as other operating expenses in the consolidated statements of operations. A reconciliation of the statutory U.S. federal income tax rate of 21% in 2019 and 2018 and of 35% in 2017 to the Company’s effective income tax rates is set forth below: For the Years Ended December 31, 2019 2018 2017 U.S. statutory tax rate 21.0 % 21.0 % 35.0 % Increase related to state and local taxes, net of U.S. income tax benefit (0.5) 2.6 (499.9) Benefits and taxes related to foreign operations 8.8 (1.5) (2,796.3) Charge related to Global Intangible Low-Taxed Income 2.0 1.3 — RSU vesting and dividend discrete accounting charge or benefit 6.3 8.0 (486.2) Charge related to non-deductible compensation 3.3 1.8 (38.7) Rate change to deferred items related to Tax Cuts and Jobs Act — — (5,193.7) Other (0.5) (0.3) 127.9 Effective income tax rate 40.4 % 32.9 % (8,851.9) % For the year ended December 31, 2017, the rate reconciliation is not meaningful principally as result of the application of various material adjustments related to the TCJA on nominal pre-tax loss for the period.

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	Note 16 — Leases The Company leases office space for its operations around the globe. On May 16, 2019, the Company entered into a new Office Lease (the “Lease”) for its new principal executive offices in New York, N.Y. Rental payments are scheduled to commence on November 1, 2020 and shall continue for a term of 15 years and 3 months. As of December 31, 2019, the Lease is not included in operating lease right-of-use assets and operating lease obligations on the consolidated statement of financial condition as the Company does not yet have the right to use the premises. All of the Company’s leases are operating leases and have remaining lease terms ranging from less than 1 year to 15.3 years. The Company incurred operating lease cost, excluding property taxes, utilities and other ancillary costs, of $15.3 million, $15.0 million and $15.0 million for the years ended December 31, 2019, 2018 and 2017, respectively, which is included in occupancy and equipment rental in the condensed consolidated statements of operations. As of December 31, 2019, the undiscounted aggregate minimum future rental payments are as follows: (in thousands) 2020 $ 15,789 2021 13,374 2022 11,795 2023 10,523 2024 9,602 Thereafter 88,757 Total lease payments 149,840 Less: minimum future rental payments for which the lease has not commenced (115,870) Total lease payments for which the Company has a right-of use-asset and corresponding liability 33,970 Less: Interest (3,220) Present value of operating lease liabilities for which the Company has a right-of-use asset and corresponding liability $ 30,750 The weighted average remaining lease term and weighted average discount rate of our operating leases are as follows: As of Weighted average remaining lease term in years, including the lease for which the right to use has not commenced 12.1 Weighted average discount rate 5.8 % As of December 31, 2018, the approximate aggregate minimum future rental payments required as presented under the historical leasing standard in ASC 840 were as follows: (in thousands) 2019 $ 15,872 2020 13,535 2021 5,153 2022 3,768 2023 3,000 Thereafter 4,629 Total lease payments $ 45,957

Regulatory

Regulatory	12 Months Ended
	Dec. 31, 2019
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
Regulatory	Note 17 — Regulatory Certain subsidiaries of the Company are subject to various regulatory requirements in the United States, the 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 December 31, 2019 and 2018, G&Co’s net capital was $24.5 million and $25.9 million, respectively, which exceeded its requirement by $23.2 million and $24.3 million, respectively. G&Co’s aggregate indebtedness to net capital ratio was 0.8 to 1 and 0.9 to 1 at December 31, 2019 and 2018, respectively. Certain distributions and other capital withdrawals of G&Co are subject to certain notifications and restrictive provisions of the Rule. As approved by FINRA in 2018, effective as of January 1, 2019, Greenhill Cogent, LP (GC LP) merged with G&Co, with G&Co being the sole surviving entity. The capital requirements did not change as a result of the merger.

Business Information

Business Information	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Business Information	Note 18 — 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 principally earns its revenues from advisory fees upon the successful completion of the client’s transaction or restructuring. In 2019, there was one client that accounted for approximately 11% of total revenues (advice to Total System Services, Inc. (TSYS) on its merger with Global Payments Inc.). For the years ended December 31, 2018 and 2017, there were no clients that accounted for more than 10% of total revenues. Since the financial markets are global in nature, the Company generally manages its business based on the operating results of the enterprise taken as whole, not by geographic region. For reporting purposes, the geographic regions are the North America, Europe, and the rest of the world, which are the locations where the Company retains substantially all of its employees. The following table presents information about the Company by geographic region, after elimination of all significant inter-company accounts and transactions: As of or for the Years Ended December 31, 2019 2018 2017 (in thousands) Revenues North America $ 212,916 $ 193,707 $ 169,502 Europe 46,827 125,149 47,441 Rest of World 41,269 33,129 22,239 Total $ 301,012 $ 351,985 $ 239,182 Operating income (loss) North America $ 38,116 $ 16,472 $ 19,887 Europe (9,964) 57,736 (10,541) Rest of World 17,691 6,660 (2,446) Total $ 45,843 $ 80,868 $ 6,900 Total assets North America $ 196,603 $ 198,313 $ 426,799 Europe 129,725 152,478 48,195 Rest of World 168,047 134,909 135,823 Total $ 494,375 $ 485,700 $ 610,817 The Company's revenues are based on the country where the services were derived. For the years ended December 31, 2019, 2018 and 2017, the Company generated 67%, 52%, and 70%, respectively, of its total revenues from the United States and 12%, 29% and 15% respectively, of its total revenues from the United Kingdom. No other country had revenues which individually represented more than 10% of the Company’s total revenues during the years ended December 31, 2019, 2018 and 2017, respectively. Included in the Company’s total assets are long-lived assets, excluding deferred tax assets and intangible assets, located in the United States of $22.8 million and $26.7 million at December 31, 2019 and 2018, respectively. No other country had long-lived assets, which individually represented more than 10% of the Company’s total long-lived assets at December 31, 2019 and 2018.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Note 19 — Subsequent Events The Company evaluates subsequent events through the date on which the financial statements are issued. On January 30, 2020, the Board of Directors of the Company declared, by unanimous written consent, a quarterly dividend of $0.05 per share. The dividend will be payable on March 18, 2020 to the common stockholders of record on March 4, 2020.

Supplemental Financial Informat

Supplemental Financial Information Quarterly Results (unaudited)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Supplemental Financial Information Quarterly Results (unaudited)	Supplemental Financial Information Quarterly Results (unaudited) The following represents the Company’s unaudited quarterly results for the years ended December 31, 2019 and 2018. These quarterly results were prepared in accordance with U.S. generally accepted accounting principles and reflect all adjustments that are, in the opinion of management, necessary for a fair presentation of the results. For the Three Months Ended March 31, June 30, Sept. 30, Dec. 31, (in millions, except per share data) Revenues $ 51.2 $ 56.1 $ 87.0 $ 106.7 Total operating expenses 65.5 62.5 61.8 65.4 Total operating income (loss) (14.3) (6.4) 25.2 41.3 Interest expense 5.8 10.6 5.7 5.2 Income (loss) before taxes (20.1) (17.0) 19.5 36.1 Provision (benefit) for taxes (4.7) (4.3) 4.5 11.9 Net income (loss) $ (15.4) $ (12.7) $ 15.0 $ 24.2 Earnings (loss) per share: Basic $ (0.64) $ (0.53) $ 0.63 $ 1.05 Diluted $ (0.64) $ (0.53) $ 0.63 $ 1.05 For the Three Months Ended March 31, June 30, Sept. 30, Dec. 31, (in millions, except per share data) Revenues $ 87.5 $ 88.5 $ 86.8 $ 89.1 Total operating expenses 68.5 69.0 66.1 67.5 Total operating income 19.0 19.5 20.7 21.6 Interest expense 5.3 5.6 5.7 5.9 Income before taxes 13.7 13.9 15.0 15.7 Provision for taxes 7.4 3.3 3.8 4.7 Net income $ 6.3 $ 10.6 $ 11.2 $ 11.0 Earnings per share: Basic $ 0.21 $ 0.39 $ 0.45 $ 0.46 Diluted $ 0.21 $ 0.38 $ 0.43 $ 0.45

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Financial Information	Basis of Financial Information These 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 compensation accruals and other matters. Management believes that the estimates used in preparing its 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 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.
Revenue Recognition	Revenue Recognition Subsequent to the adoption of ASC 606 The Company adopted ASU 2014-09, Revenue from Contracts with Customers, (codified in ASC 606) on January 1, 2018. 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 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 revenues for financing advisory and restructuring engagements as the services are provided to the client, based on the 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, deferred revenue (also known as contract liabilities) was $3.9 million, $5.6 million and $12.3 million as of December 31, 2019, December 31, 2018 and January 1, 2018, respectively. Deferred revenue is included in accounts payable and accrued expenses in the consolidated statements of financial condition. During the years ended December 31, 2019 and 2018, the Company recognized $4.7 million and $9.3 million of revenues, respectively, that were included in the deferred revenue (contract liabilities) balance at the beginning of each respective period. The Company’s clients reimburse certain expenses incurred by the Company in the conduct of advisory engagements. Client reimbursements totaled $6.4 million, $7.0 million and $4.7 million for the years ended December 31, 2019, 2018, and 2017, respectively. Such reimbursements were reported as revenues and operating expenses for the years ended December 31, 2019 and 2018, and as a reduction to operating expenses for the year ended December 31, 2017, as discussed below, with no impact to operating income in the periods presented. Prior to the adoption of ASC 606 Prior to January 1, 2018, it was the Company’s accounting policy to recognize revenue when (i) there was persuasive evidence of an arrangement with a client, (ii) the agreed-upon services had been completed and delivered to the client or the transaction or events noted in the engagement letter were determined to be substantially complete, (iii) fees were fixed and determinable, and (iv) collection was reasonably assured. The Company recognized revenues for mergers and acquisitions or financing advisory and restructuring engagements when the services related to the underlying transactions were completed in accordance with the terms of the engagement letter and all other requirements for revenue recognition were satisfied. The Company recognized capital advisory fees from primary capital raising transactions at the time of the client’s acceptance of capital or capital commitments to a fund in accordance with the terms of the engagement letter. Generally, fee revenue was determined based upon a fixed percentage of capital committed to the fund. For multiple closings, revenue was recognized at each interim closing based on the amount of capital committed at each closing at the fixed fee percentage. At the final closing, revenue was recognized at the fixed percentage for the amount of capital committed since the last interim closing. The Company recognized capital advisory fees from secondary market transactions at the time the sale or transfer of the capital interest was completed in accordance with the terms of the engagement letter. Generally, fee revenue was determined based upon a fixed percentage of the transaction value. While the majority of the Company’s fee revenue was earned at the conclusion of a transaction or closing of a fund, on-going retainer fees, substantially all of which relate to non-success based strategic advisory and financing advisory and restructuring assignments, were also earned and recognized as revenue over the period in which the related service was rendered.
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 an original maturity date of three months or less, when purchased, to be cash equivalents. Cash equivalents primarily consist of money market funds and other short-term highly liquid investments with original maturities of three months or less and are carried at cost, plus accrued interest, which approximates the fair value due to the short-term nature of these investments.
Advisory Fees Receivables	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 bad debt expense of $1.2 million, $0.3 million and $1.1 million for the years ended December 31, 2019, 2018 and 2017, respectively. Included in the fees receivable balances at December 31, 2019 and 2018 were $10.5 million and $20.0 million, respectively, of long term receivables related to primary capital advisory engagements, which are generally paid in installments over a period of three years. Credit risk related to 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. See “Note 5 — Goodwill”. 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 consolidated statements of changes in stockholders’ equity.
Compensation Payable	Compensation Payable Included in compensation payable are discretionary compensation awards comprised of annual cash bonuses and long-term incentive compensation, consisting of deferred cash retention awards, which are non-interest bearing, and generally amortized ratably over a three five
Restricted Stock Units	Restricted Stock Units The Company accounts for its share-based compensation payments by recording the fair value of restricted stock units (RSUs) granted to employees as compensation expense. The restricted stock units are generally amortized ratably over a three five 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 10 — Equity”.
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 consolidated statements of changes in stockholders’ equity. Foreign currency transaction gains and losses are included in the 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 7 — Fair Value of Financial Instruments”.
Leases	Leases The Company leases office space for its operations around the globe. Certain leases include options to renew, which can be exercised at the Company’s sole discretion. The Company determines if a contract contains a lease at contract inception. Operating lease assets represent the Company’s right to use the underlying asset and operating lease liabilities represent the Company’s obligation to make lease payments. Operating lease assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. When determining the lease term, the Company generally does not include options to renew as it is not reasonably certain at contract inception that the Company will exercise the option(s). The Company uses the implicit rate when readily determinable and its incremental borrowing rate when the implicit rate is not readily determinable. The Company’s incremental borrowing rate is determined using its secured borrowing rate and giving consideration to the currency and term of the associated lease as appropriate. The lease payments used to determine the Company’s operating lease assets may include lease incentives, stated rent increases and escalation clauses linked to rates of inflation when determinable and are recognized in operating lease assets in the condensed consolidated balance sheets. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. The straight-lining of rent expense results in differences in the operating lease right-of-use asset and operating lease obligations on the consolidated statement of financial position.
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: Equipment – 5 years Furniture and fixtures – 7 years Leasehold improvements – the lesser of 10 years or the remaining lease term
Business Information	Business InformationThe 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.
Recently Adopted Accounting Pronouncements; Accounting Developments	Recently Adopted Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases (“ASU 2016-02”), which requires the recognition of lease assets and lease liabilities for operating leases, among other changes. The Company adopted this standard on January 1, 2019 utilizing a modified retrospective approach. The Company elected to apply practical expedients provided in the standard that allowed the Company to not reassess whether expired or existing contracts are or contain leases, not reassess lease classification for expired or existing leases (e.g., pre-existing operating leases are classified as operating leases under the new standard), and not reassess initial direct costs for existing leases. The impact of adopting ASU 2016-02 was an increase of $38.1 million to the Company’s assets and liabilities for the operating lease right-of-use assets and operating lease obligations on the condensed consolidated statement of financial condition as of January 1, 2019. Upon adoption, the Company also reclassified $3.2 million of deferred rent from accounts payable and accrued expenses to operating lease obligations on the condensed consolidated statement of financial condition. Differences in the operating lease right-of-use asset and operating lease obligations are due to straight-lining rent expense and the resulting deferred rent. There was no net impact to the condensed consolidated statement of operations. 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 June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326) - Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). This ASU changes how companies measure credit losses on most financial instruments, including accounts receivable. Companies will be required to estimate lifetime expected credit losses, which is generally expected to result in earlier recognition of credit losses. The Company adopted this standard effective on January 1, 2020 under a modified retrospective approach. The Company estimates that as of January 1, 2020, the impact of adoption will decrease the Company’s assets and retained earnings by approximately $0.2 million.

Cash and Cash Equivalents (Tabl

Cash and Cash Equivalents (Tables)	12 Months Ended
	Dec. 31, 2019
Cash and Cash Equivalents [Abstract]
Schedule of Carrying Values of Cash and Cash Equivalents	The carrying values of the Company’s cash and cash equivalents are as follows: As of December 31, 2019 2018 (in thousands) Cash $ 59,455 $ 80,400 Cash equivalents 44,751 72,193 Restricted cash - letters of credit 9,769 3,781 Total cash and cash equivalents $ 113,975 $ 156,374

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Components of Property and Equipment	Property and equipment consist of the following: As of December 31, 2019 2018 (in thousands) Equipment $ 22,452 $ 21,451 Furniture and fixtures 7,758 7,684 Leasehold improvements 23,806 23,082 54,016 52,217 Less accumulated depreciation and amortization (47,735) (45,032) Total property and equipment, net $ 6,281 $ 7,185

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in Carrying Value of Goodwill	Goodwill consists of the following: As of December 31, 2019 2018 (in thousands) Balance, January 1 $ 205,922 $ 217,737 Foreign currency translation adjustments 70 (11,815) Balance, December 31 $ 205,992 $ 205,922

Other Assets (Tables)

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Other Assets	Other assets consist of the following: As of December 31, 2019 2018 (in thousands) Prepaid expenses and other assets $ 6,098 $ 5,993 Rent deposits 1,856 1,764 Other tangible assets 264 368 Total other assets $ 8,218 $ 8,125

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Liabilities Measured at Fair Value on a Recurring Basis	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 December 31, 2019 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, 2019 (in thousands) Assets Cash equivalents $ 44,751 $ — $ — $ 44,751 Total $ 44,751 $ — $ — $ 44,751 Assets Measured at Fair Value on a Recurring Basis as of December 31, 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 December 31, 2018 (in thousands) Assets Cash equivalents $ 72,193 $ — $ — $ 72,193 Total $ 72,193 $ — $ — $ 72,193 Liabilities Measured at Fair Value on a Recurring Basis 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 were to be made if secondary capital advisory revenues of $80.0 million or more were earned during either the two two two two 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 prior to its settlement in April 2019. The liability arose as a result of the acquisition of Cogent and was categorized as a Level 3 liability. Through March 31, 2019, the liability was remeasured each quarter based on the probability of achieving the target revenue threshold and weighted average discount rate as discussed below. In the third quarter of 2018, the liability was transferred to Level 2 as the only remaining fair value input was the present value discount. Liabilities Measured at Fair Value on a Recurring Basis as of December 31, 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 December 31, 2018 (in thousands) Liabilities Contingent obligation due selling unitholders of Cogent $ — $ 18,293 $ — $ 18,293 Total $ — $ 18,293 $ — $ 18,293
Changes in Level 3 Measured at Fair Value	Changes in Level 3 liabilities measured at fair value on a recurring basis for the year ended December 31, 2018 Opening Balance as of January 1, 2018 Total realized and unrealized gains (losses) included in Net Income Unrealized gains (losses) included in Other Comprehensive Income Purchases Issues Sales Transfers Out Closing Balance as of December 31, 2018 Unrealized gains (losses) for Level 3 liabilities outstanding at December 31, 2018 (in thousands) Liabilities Contingent obligation due selling unitholders of Cogent $ 13,763 $ (4,021) $ — $ — $ — $ — $ (17,784) $ — $ — Total $ 13,763 $ (4,021) $ — $ — $ — $ — $ (17,784) $ — $ — Changes in Level 3 liabilities measured at fair value on a recurring basis for the year ended December 31, 2017 Opening Balance as of January 1, 2017 Total realized and unrealized gains (losses) included in Net Income Unrealized gains (losses) included in Other Comprehensive Income Purchases Issues Sales Transfers Out Closing Balance as of December 31, 2017 Unrealized gains (losses) for Level 3 liabilities outstanding at December 31, 2017 (in thousands) Liabilities Contingent obligation due selling unitholders of Cogent $ 15,095 $ 1,332 $ — $ — $ — $ — $ — $ 13,763 $ 1,332 Total $ 15,095 $ 1,332 $ — $ — $ — $ — $ — $ 13,763 $ 1,332

Loan Facilities (Tables)

Loan Facilities (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Long-term Debt	As of December 31, 2019 2018 (in thousands) Term Loan Facility carrying value $ 358,003 $ 319,479 Unamortized discount 2,365 1,313 Unamortized debt issuance costs 5,257 7,333 Total Term Loan Facility 365,625 328,125 Current maturities of Term Loan Facility (18,750) (35,000) Total long-term debt $ 346,875 $ 293,125

Earnings per Share (Tables)

Earnings per Share (Tables)	12 Months Ended
	Dec. 31, 2019
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 Years Ended December 31, 2019 2018 2017 (in thousands, except per share amounts) Numerator for basic and diluted EPS — net income (loss) $ 10,978 $ 39,222 $ (26,651) Denominator for basic EPS — weighted average number of shares 24,025 26,813 32,075 Add — dilutive effect of: Restricted stock units and Cogent Earnout shares 247 (1) 825 (1) — (1) Denominator for diluted EPS — weighted average number of shares and dilutive securities 24,272 27,638 32,075 Earnings (loss) per share: Basic EPS $ 0.46 $ 1.46 $ (0.83) Diluted EPS $ 0.45 $ 1.42 $ (0.83)

Deferred Compensation (Tables)

Deferred Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Restricted Stock Units Activity	The activity related to the restricted stock units is set forth below: Restricted Stock Units Outstanding 2019 2018 Units Grant Date Weighted Average Fair Value Units Grant Date Weighted Average Fair Value Outstanding, January 1, 6,210,282 $ 22.73 5,396,728 $ 28.02 Granted 2,294,967 22.55 2,741,343 18.94 Delivered (1,468,700) 27.58 (1,265,500) 36.63 Forfeited (255,074) 22.84 (662,289) 23.49 Outstanding, December 31, 6,781,475 $ 21.60 6,210,282 $ 22.73

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Components of Provision for Income Taxes	The components of the provision for income taxes reflected on the consolidated statements of operations are set forth below: For the Years Ended December 31, 2019 2018 2017 (in thousands) Current taxes: U.S. federal $ 2,868 $ 1,868 $ 8,792 State and local 410 1,937 1,181 Foreign 4,982 9,968 1,786 Total current tax expense 8,260 13,773 11,759 Deferred taxes: U.S. federal 293 202 14,626 State and local (534) 50 795 Foreign (574) 5,183 (827) Total deferred tax (benefit) expense (815) 5,435 14,594 Total tax expense $ 7,445 $ 19,208 $ 26,353
Significant Components of Net Deferred Tax Assets and Liabilities	Significant components of the Company’s net deferred tax assets and liabilities are set forth below: As of December 31, 2019 2018 (in thousands) Deferred tax assets: Compensation and benefits $ 21,706 $ 19,353 Depreciation and amortization 1,816 1,539 Cumulative translation adjustment 12,235 12,624 Operating loss carryforwards 4,644 5,256 Capital loss carryforwards 1,874 1,909 Lease asset 7,652 — Other financial accruals 3,760 5,488 Valuation allowances (2,409) (2,463) Total deferred tax assets 51,278 43,706 Deferred tax liabilities: Lease liability 6,959 — Other financial accruals 5,045 3,990 Total deferred tax liabilities 12,004 3,990 Net deferred tax asset $ 39,274 $ 39,716
Reconciliation of Statutory U.S. Federal Income Tax Rate to Company's Effective Income Tax Rate	A reconciliation of the statutory U.S. federal income tax rate of 21% in 2019 and 2018 and of 35% in 2017 to the Company’s effective income tax rates is set forth below: For the Years Ended December 31, 2019 2018 2017 U.S. statutory tax rate 21.0 % 21.0 % 35.0 % Increase related to state and local taxes, net of U.S. income tax benefit (0.5) 2.6 (499.9) Benefits and taxes related to foreign operations 8.8 (1.5) (2,796.3) Charge related to Global Intangible Low-Taxed Income 2.0 1.3 — RSU vesting and dividend discrete accounting charge or benefit 6.3 8.0 (486.2) Charge related to non-deductible compensation 3.3 1.8 (38.7) Rate change to deferred items related to Tax Cuts and Jobs Act — — (5,193.7) Other (0.5) (0.3) 127.9 Effective income tax rate 40.4 % 32.9 % (8,851.9) %

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Schedule of undiscounted aggregate minimum future rental payments	As of December 31, 2019, the undiscounted aggregate minimum future rental payments are as follows: (in thousands) 2020 $ 15,789 2021 13,374 2022 11,795 2023 10,523 2024 9,602 Thereafter 88,757 Total lease payments 149,840 Less: minimum future rental payments for which the lease has not commenced (115,870) Total lease payments for which the Company has a right-of use-asset and corresponding liability 33,970 Less: Interest (3,220) Present value of operating lease liabilities for which the Company has a right-of-use asset and corresponding liability $ 30,750
Schedule of weighted average remaining lease term and weighted average discount rate for operating leases	The weighted average remaining lease term and weighted average discount rate of our operating leases are as follows: As of Weighted average remaining lease term in years, including the lease for which the right to use has not commenced 12.1 Weighted average discount rate 5.8 %
Schedule of Future Minimum Rental Payments for Operating Leases	As of December 31, 2018, the approximate aggregate minimum future rental payments required as presented under the historical leasing standard in ASC 840 were as follows: (in thousands) 2019 $ 15,872 2020 13,535 2021 5,153 2022 3,768 2023 3,000 Thereafter 4,629 Total lease payments $ 45,957

Business Information (Tables)

Business Information (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Information by Geographic Region, After Elimination of All Significant Inter-company Accounts and Transactions	The following table presents information about the Company by geographic region, after elimination of all significant inter-company accounts and transactions: As of or for the Years Ended December 31, 2019 2018 2017 (in thousands) Revenues North America $ 212,916 $ 193,707 $ 169,502 Europe 46,827 125,149 47,441 Rest of World 41,269 33,129 22,239 Total $ 301,012 $ 351,985 $ 239,182 Operating income (loss) North America $ 38,116 $ 16,472 $ 19,887 Europe (9,964) 57,736 (10,541) Rest of World 17,691 6,660 (2,446) Total $ 45,843 $ 80,868 $ 6,900 Total assets North America $ 196,603 $ 198,313 $ 426,799 Europe 129,725 152,478 48,195 Rest of World 168,047 134,909 135,823 Total $ 494,375 $ 485,700 $ 610,817

Supplemental Financial Inform_2

Supplemental Financial Information Quarterly Results (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Unaudited Quarterly Results	The following represents the Company’s unaudited quarterly results for the years ended December 31, 2019 and 2018. These quarterly results were prepared in accordance with U.S. generally accepted accounting principles and reflect all adjustments that are, in the opinion of management, necessary for a fair presentation of the results. For the Three Months Ended March 31, June 30, Sept. 30, Dec. 31, (in millions, except per share data) Revenues $ 51.2 $ 56.1 $ 87.0 $ 106.7 Total operating expenses 65.5 62.5 61.8 65.4 Total operating income (loss) (14.3) (6.4) 25.2 41.3 Interest expense 5.8 10.6 5.7 5.2 Income (loss) before taxes (20.1) (17.0) 19.5 36.1 Provision (benefit) for taxes (4.7) (4.3) 4.5 11.9 Net income (loss) $ (15.4) $ (12.7) $ 15.0 $ 24.2 Earnings (loss) per share: Basic $ (0.64) $ (0.53) $ 0.63 $ 1.05 Diluted $ (0.64) $ (0.53) $ 0.63 $ 1.05 For the Three Months Ended March 31, June 30, Sept. 30, Dec. 31, (in millions, except per share data) Revenues $ 87.5 $ 88.5 $ 86.8 $ 89.1 Total operating expenses 68.5 69.0 66.1 67.5 Total operating income 19.0 19.5 20.7 21.6 Interest expense 5.3 5.6 5.7 5.9 Income before taxes 13.7 13.9 15.0 15.7 Provision for taxes 7.4 3.3 3.8 4.7 Net income $ 6.3 $ 10.6 $ 11.2 $ 11.0 Earnings per share: Basic $ 0.21 $ 0.39 $ 0.45 $ 0.46 Diluted $ 0.21 $ 0.38 $ 0.43 $ 0.45

Organization (Details)

Organization (Details)	Dec. 31, 2019state
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of states in which entity is licensed to operate (states)	50

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)Segment	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Jan. 01, 2020USD ($)	Jan. 01, 2019USD ($)	Jan. 01, 2018USD ($)
Significant Accounting Policies [Line Items]
Contract with customer, liability	$ 3,900	$ 5,600				$ 12,300
Allowance for doubtful accounts	1,197	0	$ 0
Long term receivables related to primary capital advisory engagements	$ 10,500	20,000
Installments period	3 years
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.
Number of business segments (segment) | Segment	1
Operating lease right-of-use asset	$ 28,346
Operating lease obligations	30,750
Total assets	494,375	485,700	610,817
Retained earnings	$ 69,093	63,427
Accounting Standards Update 2016-02
Significant Accounting Policies [Line Items]
Operating lease right-of-use asset					$ 38,100
Operating lease obligations					38,100
Deferred rent					$ (3,200)
Equipment
Significant Accounting Policies [Line Items]
Estimated useful lives of fixed assets (or lesser for Leaseholds)	5 years
Furniture and fixtures
Significant Accounting Policies [Line Items]
Estimated useful lives of fixed assets (or lesser for Leaseholds)	7 years
Leasehold improvements
Significant Accounting Policies [Line Items]
Estimated useful lives of fixed assets (or lesser for Leaseholds)	10 years
Minimum
Significant Accounting Policies [Line Items]
Amortization period of deferred cash retention awards	3 years
Minimum | Restricted Stock
Significant Accounting Policies [Line Items]
Amortization period of restricted stock units	3 years
Maximum
Significant Accounting Policies [Line Items]
Amortization period of deferred cash retention awards	5 years
Maximum | Restricted Stock
Significant Accounting Policies [Line Items]
Amortization period of restricted stock units	5 years
Reimbursement Revenue [Member]
Significant Accounting Policies [Line Items]
Revenue from contract with customer, excluding assessed tax	$ 6,400	7,000	4,700
Advisory Fees [Member]
Significant Accounting Policies [Line Items]
Allowance for doubtful accounts	1,200	300	$ 1,100
Advisory Services
Significant Accounting Policies [Line Items]
Contract with customer, liability, revenue recognized	$ 4,700	$ 9,300
Forecast | Accounting Standards Update 2016-13
Significant Accounting Policies [Line Items]
Total assets				$ (200)
Retained earnings				$ (200)

Cash and Cash Equivalents (Deta

Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restricted Cash and Cash Equivalents Items [Line Items]
Cash	$ 59,455	$ 80,400
Cash equivalents	44,751	72,193
Restricted cash - letters of credit	9,800	3,800
Total cash and cash equivalents	113,975	156,374	$ 267,646	$ 98,313
Letter of Credit
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash - letters of credit	$ 9,769	$ 3,781

Cash and Cash Equivalents - Nar

Cash and Cash Equivalents - Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2024	Jun. 30, 2019
Cash and Cash Equivalents [Abstract]
Letters of credit outstanding, amount		$ 5.9
Cash and Cash Equivalents [Line Items]
Letters of credit outstanding, amount		$ 5.9
Forecast
Cash and Cash Equivalents [Abstract]
Letters of credit outstanding, amount	$ 3.5
Cash and Cash Equivalents [Line Items]
Letters of credit outstanding, amount	$ 3.5

Property and Equipment - Compon

Property and Equipment - Components of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Equipment	$ 22,452	$ 21,451
Furniture and fixtures	7,758	7,684
Leasehold improvements	23,806	23,082
Property, plant and equipment, gross	54,016	52,217
Less accumulated depreciation and amortization	(47,735)	(45,032)
Total property and equipment, net	$ 6,281	$ 7,185

Goodwill - Changes in Carrying

Goodwill - Changes in Carrying Value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill
Balance, January 1	$ 205,922	$ 217,737
Foreign currency translation adjustments	70	(11,815)
Balance, December 31	$ 205,992	$ 205,922

Goodwill - Additional Informati

Goodwill - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Impairment loss	$ 0	$ 0	$ 0

Other Assets - Components of Ot

Other Assets - Components of Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses and other assets	$ 6,098	$ 5,993
Rent deposits	1,856	1,764
Other tangible assets	264	368
Total other assets	$ 8,218	$ 8,125

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Liabilities
Contingent obligation due selling unitholders of Cogent	$ 0	$ 18,293
Fair Value, Measurements, Recurring
Assets
Cash and cash equivalents	44,751	72,193
Assets, Fair Value Disclosure, Recurring (Deprecated 2018-01-31)	44,751	72,193
Liabilities
Contingent obligation due selling unitholders of Cogent		18,293
Total		18,293
Quoted Prices in Active  Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring
Assets
Cash and cash equivalents	44,751	72,193
Assets, Fair Value Disclosure, Recurring (Deprecated 2018-01-31)	44,751	72,193
Liabilities
Contingent obligation due selling unitholders of Cogent		0
Total		0
Significant Other Observable  Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets
Cash and cash equivalents	0	0
Assets, Fair Value Disclosure, Recurring (Deprecated 2018-01-31)	0	0
Liabilities
Contingent obligation due selling unitholders of Cogent		18,293
Total		18,293
Significant Unobservable  Inputs (Level 3) | Fair Value, Measurements, Recurring
Assets
Cash and cash equivalents	0	0
Assets, Fair Value Disclosure, Recurring (Deprecated 2018-01-31)	$ 0	0
Liabilities
Contingent obligation due selling unitholders of Cogent		0
Total		$ 0

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Changes in Level 3 Liabilities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening Balance	$ 13,763,000	$ 15,095,000
Total realized and unrealized gains (losses) included in Net Income	(4,021,000)	1,332,000
Unrealized gains (losses) included in Other Comprehensive Income	0	0
Purchases	0	0
Issues	0	0
Sales	0	0
Transfers Out	(17,784,000)	0
Closing Balance	0	13,763,000
Unrealized gains (losses) for Level 3 liabilities outstanding at end of the period	0	1,332,000
Contingent Consideration Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening Balance	13,763,000	15,095,000
Total realized and unrealized gains (losses) included in Net Income	(4,021,000)	1,332,000
Unrealized gains (losses) included in Other Comprehensive Income	0	0
Purchases	0	0
Issues	0	0
Sales	0	0
Transfers Out	(17,784,000)	0
Closing Balance	0	13,763,000
Unrealized gains (losses) for Level 3 liabilities outstanding at end of the period	$ 0	$ 1,332,000

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Narrative (Details) - USD ($) $ in Thousands	Apr. 01, 2015	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Revenue target	$ 80,000
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
Distribution period ending On March 31 2017 (years)	2 years
Distribution period ending On March 31 2019 (years)	2 years
Contingent obligation due selling unitholders of Cogent		$ 0	$ 18,293
Increase (decrease) in fair value of contingent obligation		575	4,531	$ (1,332)
Cogent Partners, LP
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration, cash	$ 18,900
Possible contingent consideration (shares)	334,048
Contingent obligation due selling unitholders of Cogent	$ 13,100
Increase (decrease) in fair value of contingent obligation		$ 600	$ 4,500	$ (1,300)

Related Parties (Details)

Related Parties (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
Related Party Transaction [Line Items]
Due to affiliates	$ 0		$ 0
Board of Directors Chairman
Related Party Transaction [Line Items]
Rent reimbursements related to sublease	100,000
Sublease
Related Party Transaction [Line Items]
Payment for use of aircraft owned by executive	$ 100,000	$ 100,000

Loan Facilities - Additional In

Loan Facilities - Additional Information (Detail) - USD ($)	Apr. 30, 2019	Apr. 12, 2019	Oct. 12, 2017	Oct. 31, 2017	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Apr. 13, 2019
Line of Credit Facility [Line Items]
Repayments of lines of credit						$ 0	$ 0	$ 133,425,000
Proceeds from secured term loan, net						48,248,000	0	339,048,000
Debt, discount						2,365,000	1,313,000
Deferred financing costs						5,257,000	$ 7,333,000
Weighted average interest rate							4.20%
Long-term Debt, Gross						365,625,000	$ 328,125,000
Unamortized debt issuance costs						5,257,000	7,333,000
Unamortized discount						2,365,000	1,313,000
Repayments of bank term loans						0	$ 0	$ 16,875,000
Revolving credit facility
Line of Credit Facility [Line Items]
Amount repaid				$ 83,800,000
Interest rate							3.50%
Weighted average daily borrowings outstanding under the loan facility							$ 65,300,000
Revolving credit facility | U.S. Prime Rate
Line of Credit Facility [Line Items]
Spread on interest rate							4.25%
Secured debt | Term loan
Line of Credit Facility [Line Items]
Annual principal payments						8,800,000
Recapitalization credit agreement | Secured debt
Line of Credit Facility [Line Items]
Incremental expense related to the amortization of debt issuance costs					$ 2,300,000	$ 1,900,000
Recapitalization credit agreement | Secured debt | United States
Line of Credit Facility [Line Items]
Collateral percentage, capital stock of subsidiary						100.00%
Recapitalization credit agreement | Secured debt | Non-US
Line of Credit Facility [Line Items]
Collateral percentage, capital stock of subsidiary						65.00%
Recapitalization credit agreement | Secured debt | Term loan
Line of Credit Facility [Line Items]
Principal payments						$ 18,100,000
Period of time required before year end to make annual prepayments of principal						90 days
Annual prepayment of principal, percentage amount of annual excess cash flow						50.00%
Percentage of redemption price						101.00%
Recapitalization credit agreement | Secured debt | Revolving credit facility
Line of Credit Facility [Line Items]
Covenant, leverage ratio, excess borrowings, minimum						$ 12,500,000
Term Loan Facility | Secured debt | Term loan
Line of Credit Facility [Line Items]
Face amount of debt			$ 350,000,000
Debt term			5 years
Long-term debt, weighted average interest rate, over time					5.80%
Term Loan Facility | Secured debt | Term loan | Minimum
Line of Credit Facility [Line Items]
Weighted average interest rate			5.10%			5.00%
Term Loan Facility | Secured debt | Term loan | Maximum
Line of Credit Facility [Line Items]
Weighted average interest rate			6.60%			6.60%
Revolving Loan Facility | Secured debt | Revolving credit facility
Line of Credit Facility [Line Items]
Face amount of debt			$ 20,000,000
Debt term			3 years
Long-term Debt, Gross						$ 0	$ 0
New TLB | Secured debt
Line of Credit Facility [Line Items]
Debt, discount	$ 9,000,000
Annual principal payments						$ 9,400,000
Unamortized discount	9,000,000
New TLB | Secured debt | Base rate
Line of Credit Facility [Line Items]
Spread on interest rate						2.25%
New TLB | Secured debt | Term loan
Line of Credit Facility [Line Items]
Face amount of debt		$ 375,000,000
Debt term		5 years
Repayments of lines of credit		$ 319,400,000
Proceeds from secured term loan, net						$ 48,200,000
Deferred financing costs		2,700,000							$ 1,800,000
Long-term debt, weighted average interest rate, over time						5.70%
Debt Instrument, Incurred Fees		5,700,000
Unamortized debt issuance costs		2,700,000							$ 1,800,000
Write off of Deferred Debt Issuance Cost	$ 3,000,000	4,800,000
Debt instrument, periodic payment, principal		4,700,000
Debt instrument, annual principal payment		$ 18,800,000
New TLB | Secured debt | Term loan | LIBOR
Line of Credit Facility [Line Items]
Spread on interest rate		3.25%

Loan Facilities - Schedule of D

Loan Facilities - Schedule of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Secured term loan payable	$ 358,003	$ 319,479
Unamortized discount	2,365	1,313
Unamortized debt issuance costs	5,257	7,333
Total Term Loan Facility	365,625	328,125
Current maturities of Term Loan Facility	(18,750)	(35,000)
Total long-term debt	$ 346,875	$ 293,125

Equity (Details)

Equity (Details) - USD ($)	Apr. 01, 2015	Nov. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Apr. 30, 2019	Sep. 30, 2017
Equity, Class of Treasury Stock [Line Items]
Cost of repurchased common stock			$ 69,439,000	$ 195,299,000	$ 79,561,000
Dividends declared per common share (usd per share)			$ 0.20	$ 0.20	$ 1.40
Dividend equivalents paid on outstanding restricted stock units			$ 1,300,000	$ 1,100,000	$ 6,300,000
Common stock
Equity, Class of Treasury Stock [Line Items]
Repurchased common stock (shares)			3,275,641	7,497,635	3,777,548
Average repurchase price of common stock (usd per share)			$ 16.93	$ 24.89	$ 17.41
Cost of repurchased common stock			$ 55,500,000		$ 65,800,000
Restricted stock units
Equity, Class of Treasury Stock [Line Items]
Restricted stock units vested and issued as common stock (shares)			1,407,095	1,238,733
Repurchased shares for award (shares)			573,472	433,507
Average repurchase price of shares for award (usd per share)			$ 24.37	$ 20
Treasury stock, value, acquired, cost method			$ 14,000,000	$ 8,700,000
Cogent Partners, LP
Equity, Class of Treasury Stock [Line Items]
Common stock issued on acquisition date (in shares)	779,454
Possible contingent consideration (shares)	334,048
Fair value of contingent common shares	$ 11,900,000
Chairman
Equity, Class of Treasury Stock [Line Items]
Company stock sold per transaction		$ 10,000,000
Company stock sold, total		$ 20,000,000
Total common shares issued (in shares)		1,159,420
Common stock
Equity, Class of Treasury Stock [Line Items]
Cost of repurchased common stock				186,600,000
Share repurchase program, September 2017 | Common stock
Equity, Class of Treasury Stock [Line Items]
Authorized repurchase amount (up to)								$ 285,000,000
Repurchased common stock (shares)						14,550,824
Average repurchase price of common stock (usd per share)						$ 21.16
Cost of repurchased common stock						$ 307,900,000
Fees and expenses related to tender offer				$ 200,000	$ 700,000
Remaining authorization under share repurchase plan			$ 31,200,000			$ 31,200,000
Stock Repurchase Program Authorized in April 2019 | Common stock
Equity, Class of Treasury Stock [Line Items]
Authorized repurchase amount (up to)							$ 339,100,000
Increase (decrease) In authorized amount							$ 75,000,000

Earnings per Share - Reconcilia

Earnings per Share - Reconciliation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Numerator for basic and diluted EPS — net income (loss)									$ 10,978	$ 39,222	$ (26,651)
Denominator for basic EPS — weighted average number of shares (shares)									24,024,674	26,813,285	32,074,894
Add — dilutive effect of:
Restricted stock units and Cogent Earnout shares									247,000	825,000	0
Denominator for diluted EPS — weighted average number of shares and dilutive potential shares (shares)									24,272,479	27,637,720	32,074,894
Earnings (loss) per share:
Basic (usd per share)	$ 1.05	$ 0.63	$ (0.53)	$ (0.64)	$ 0.46	$ 0.45	$ 0.39	$ 0.21	$ 0.46	$ 1.46	$ (0.83)
Diluted (usd per share)	$ 1.05	$ 0.63	$ (0.53)	$ (0.64)	$ 0.45	$ 0.43	$ 0.38	$ 0.21	$ 0.45	$ 1.42	$ (0.83)

Earnings per Share - Additional

Earnings per Share - Additional Information (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share Disclosure [Line Items]
Antidilutive securities (shares)	1,480,056	672,518	2,617,043
Cogent Partners, LP
Earnings Per Share Disclosure [Line Items]
Incremental common shares attributable to dilutive effect of contingently issuable shares (shares)		334,048

Retirement Plan (Details)

Retirement Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Incurred costs for contributions to retirement plan	$ 1	$ 1.3	$ 1.6
Contributions due to Retirement Plan included in compensation payable	$ 0.1	$ 0.1

Deferred Compensation - Additio

Deferred Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share Based Payments Disclosure [Line Items]
Description of vesting term for awards granted	Awards granted under the plan are generally amortized ratably over a three to five-year service period following the date of the grant.
Deferred compensation payable	$ 14.5	$ 12.1
Unrecognized deferred cash compensation (prior to the consideration of forfeitures)	$ 6
Deferred compensation arrangement with individual, maximum contractual term	8 months 12 days
Compensation expense from deferred compensation	$ 8.9	7.7	$ 13.1
Minimum
Share Based Payments Disclosure [Line Items]
Service period for deferred compensation payable	3 years
Maximum
Share Based Payments Disclosure [Line Items]
Service period for deferred compensation payable	5 years
Restricted stock units
Share Based Payments Disclosure [Line Items]
Compensation expense from the vesting of restricted stock units	$ 45.8	$ 38.4	$ 40.2
Weighted average grant date fair value for restricted stock units granted (usd per share)	$ 22.55	$ 18.94	$ 20.87
Unrecognized restricted stock units compensation expense	$ 58.4
Unrecognized restricted stock units compensation expense, weighted average recognition period	1 year 8 months 12 days
Restricted stock units | Minimum
Share Based Payments Disclosure [Line Items]
Stock units granted, ratable vesting period	3 years
Restricted stock units | Maximum
Share Based Payments Disclosure [Line Items]
Stock units granted, ratable vesting period	5 years

Deferred Compensation - Activit

Deferred Compensation - Activity (Detail) - Restricted stock units - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Units
Outstanding, beginning of period (shares)	6,210,282	5,396,728
Granted (shares)	2,294,967	2,741,343
Delivered (shares)	(1,468,700)	(1,265,500)
Forfeited (shares)	(255,074)	(662,289)
Outstanding, end of period (shares)	6,781,475	6,210,282	5,396,728
Grant Date Weighted Average Fair Value
Outstanding, beginning of period (usd per share)	$ 22.73	$ 28.02
Granted (usd per share)	22.55	18.94	$ 20.87
Delivered (usd per share)	27.58	36.63
Forfeited (usd per share)	22.84	23.49
Outstanding, end of period (usd per share)	$ 21.60	$ 22.73	$ 28.02

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019USD ($)CreditFacility	Dec. 31, 2018USD ($)CreditFacility	Dec. 31, 2017USD ($)
Commitments and Contingencies Disclosure [Line Items]
Proceeds from lines of credit	$ 0	$ 0	$ 69,355,000
Letter of Credit
Commitments and Contingencies Disclosure [Line Items]
Number of letters of credit issued to secure office space leases (credit facility) | CreditFacility	6	5
Amount outstanding on letters of credit	$ 9,800,000	$ 3,800,000
Proceeds from lines of credit	$ 0	$ 0

Income Taxes - Provision for In

Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current taxes:
U.S. federal									$ 2,868	$ 1,868	$ 8,792
State and local									410	1,937	1,181
Foreign									4,982	9,968	1,786
Total current tax expense									8,260	13,773	11,759
Deferred taxes:
U.S. federal									293	202	14,626
State and local									(534)	50	795
Foreign									(574)	5,183	(827)
Total deferred tax (benefit) expense									(815)	5,435	14,594
Total tax expense	$ 11,900	$ 4,500	$ (4,300)	$ (4,700)	$ 4,700	$ 3,800	$ 3,300	$ 7,400	$ 7,445	$ 19,208	$ 26,353

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclsoure [Line Items]
U.S. statutory tax rate	21.00%	21.00%	35.00%
Revaluation of deferred tax assets and liabilities, resulting in a net charge			$ 15,400
Foreign loss carryforwards	$ 14,700
Carryforward period	6 years
Deferred tax asset, net of valuation allowance	$ 51,278	$ 43,706
Foreign Tax Authority | Her Majesty's Revenue and Customs (HMRC)
Income Tax Disclsoure [Line Items]
Deferred tax asset, net of valuation allowance	1,900
Carryforward limitation, 3 to 5 years
Income Tax Disclsoure [Line Items]
Operating loss carryforwards, valuation allowance	$ 500

Income Taxes - Net Deferred Tax

Income Taxes - Net Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Compensation and benefits	$ 21,706	$ 19,353
Depreciation and amortization	1,816	1,539
Cumulative translation adjustment	12,235	12,624
Operating loss carryforwards	4,644	5,256
Capital loss carryforwards	1,874	1,909
Lease asset	7,652
Other financial accruals	3,760	5,488
Valuation allowances	(2,409)	(2,463)
Total deferred tax assets	51,278	43,706
Deferred tax liabilities:
Lease liability	6,959
Other financial accruals	5,045	3,990
Total deferred tax liabilities	12,004	3,990
Net deferred tax asset	$ 39,274	$ 39,716

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Statutory U.S. Federal Income Tax Rate to Company's Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
U.S. statutory tax rate	21.00%	21.00%	35.00%
Increase related to state and local taxes, net of U.S. income tax benefit	(0.50%)	2.60%	(499.90%)
Benefits and taxes related to foreign operations	8.80%	(1.50%)	(2796.30%)
Charge related to Global Intangible Low-Taxed Income	2.00%	1.30%	0.00%
RSU vesting and dividend discrete accounting charge or benefit	6.30%	8.00%	(486.20%)
Charge related to non-deductible compensation	3.30%	1.80%	(38.70%)
Rate change to deferred items related to Tax Cuts and Jobs Act	0.00%	0.00%	(5193.70%)
Other	(0.50%)	(0.30%)	127.90%
Effective income tax rate	40.40%	32.90%	(8851.90%)

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lessee, Lease, Description [Line Items]
Lessor, operating lease, term of contract	15 years 3 months
Weighted average remaining lease term in years, including the lease for which the right to use has not commenced	12 years 1 month 6 days
Operating lease cost	$ 15.3	$ 15	$ 15
Minimum
Lessee, Lease, Description [Line Items]
Weighted average remaining lease term in years, including the lease for which the right to use has not commenced	1 year
Maximum
Lessee, Lease, Description [Line Items]
Weighted average remaining lease term in years, including the lease for which the right to use has not commenced	15 years 3 months 18 days

Leases - Operating lease,future

Leases - Operating lease,future rental payments, maturity (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
2020	$ 15,789
2021	13,374
2022	11,795
2023	10,523
2024	9,602
Thereafter	88,757
Total lease payments	149,840
Less: minimum future rental payments for which the lease has not commenced	(115,870)
Total lease payments for which the Company has a right-of use-asset and corresponding liability	33,970
Less: Interest	(3,220)
Operating lease obligations	$ 30,750

Leases - Weighted average remai

Leases - Weighted average remaining lease term and weighted average discount rate (Details)	Dec. 31, 2019
Leases [Abstract]
Weighted average remaining lease term in years, including the lease for which the right to use has not commenced	12 years 1 month 6 days
Weighted average discount rate	5.80%

Leases - Aggregate Minimum Futu

Leases - Aggregate Minimum Future Rental Payments (Details) $ in Thousands	Dec. 31, 2018USD ($)
Leases [Abstract]
2019	$ 15,872
2020	13,535
2021	5,153
2022	3,768
2023	3,000
Thereafter	4,629
Total lease payments	$ 45,957

Regulatory - Additional Informa

Regulatory - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
Description of minimum net capital requirements	The greater of $5,000 or 1/15 of aggregate indebtedness
Minimum net capital requirements (greater than $5,000 or 1/15 of aggregate indebtedness)	$ 5,000
Minimum net capital requirements (greater than $5,000 or 1/15 of aggregate indebtedness)	6.67%
Net capital	$ 24,500,000	$ 25,900,000
Excess net capital	$ 23,200,000	$ 24,300,000
Aggregate indebtedness to net capital ratio	0.8	0.9

Business Information - Addition

Business Information - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)SegmentEntity	Dec. 31, 2018USD ($)Entity	Dec. 31, 2017Entity
Segment Reporting Information [Line Items]
Number of business segments (segment) | Segment	1
United States
Segment Reporting Information [Line Items]
Long-lived assets | $	$ 22.8	$ 26.7
Revenue | Geographic Concentration Risk | United States
Segment Reporting Information [Line Items]
Percentage of revenue	67.00%	52.00%	70.00%
Revenue | Geographic Concentration Risk | United Kingdom
Segment Reporting Information [Line Items]
Percentage of revenue	12.00%	29.00%	15.00%
Revenue | Customer Concentration Risk
Segment Reporting Information [Line Items]
Percentage of revenue	11.00%
Number of clients that accounted for more than 10% of total revenues (entity)	1
Advisory Services
Segment Reporting Information [Line Items]
Number of clients that accounted for more than 10% of total revenues (entity)		0	0

Business Information - Informat

Business Information - Information by Geographic Region, After Elimination of All Significant Inter-company Accounts and Transactions (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 106,700	$ 87,000	$ 56,100	$ 51,200	$ 89,100	$ 86,800	$ 88,500	$ 87,500	$ 301,012	$ 351,985	$ 239,182
Operating income (loss)	41,300	$ 25,200	$ (6,400)	$ (14,300)	21,600	$ 20,700	$ 19,500	$ 19,000	45,843	80,868	6,900
Total assets	494,375				485,700				494,375	485,700	610,817
North America
Segment Reporting Information [Line Items]
Revenues									212,916	193,707	169,502
Operating income (loss)									38,116	16,472	19,887
Total assets	196,603				198,313				196,603	198,313	426,799
Europe
Segment Reporting Information [Line Items]
Revenues									46,827	125,149	47,441
Operating income (loss)									(9,964)	57,736	(10,541)
Total assets	129,725				152,478				129,725	152,478	48,195
Rest of World
Segment Reporting Information [Line Items]
Revenues									41,269	33,129	22,239
Operating income (loss)									17,691	6,660	(2,446)
Total assets	$ 168,047				$ 134,909				$ 168,047	$ 134,909	$ 135,823

Subsequent Events (Details)

Subsequent Events (Details) - $ / shares	Jan. 30, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Subsequent Event [Line Items]
Dividends declared per common share (usd per share)		$ 0.20	$ 0.20	$ 1.40
Subsequent event
Subsequent Event [Line Items]
Dividends declared per common share (usd per share)	$ 0.05
Dividend payable date	Mar. 18, 2020
Dividend record date	Mar. 4, 2020

Supplemental Financial Inform_3

Supplemental Financial Information Quarterly Results (unaudited) - Schedule of Unaudited Quarterly Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Selected Quarterly Financial Information [Abstract]
Revenues	$ 106,700	$ 87,000	$ 56,100	$ 51,200	$ 89,100	$ 86,800	$ 88,500	$ 87,500	$ 301,012	$ 351,985	$ 239,182
Total operating expenses	65,400	61,800	62,500	65,500	67,500	66,100	69,000	68,500	255,169	271,117	232,282
Total operating income	41,300	25,200	(6,400)	(14,300)	21,600	20,700	19,500	19,000	45,843	80,868	6,900
Interest expense	5,200	5,700	10,600	5,800	5,900	5,700	5,600	5,300	27,420	22,438	7,198
Income (loss) before taxes	36,100	19,500	(17,000)	(20,100)	15,700	15,000	13,900	13,700	18,423	58,430	(298)
Provision (benefit) for taxes	11,900	4,500	(4,300)	(4,700)	4,700	3,800	3,300	7,400	7,445	19,208	26,353
Net income (loss)	$ 24,200	$ 15,000	$ (12,700)	$ (15,400)	$ 11,000	$ 11,200	$ 10,600	$ 6,300	$ 10,978	$ 39,222	$ (26,651)
Earnings (loss) per share:
Basic (usd per share)	$ 1.05	$ 0.63	$ (0.53)	$ (0.64)	$ 0.46	$ 0.45	$ 0.39	$ 0.21	$ 0.46	$ 1.46	$ (0.83)
Diluted (usd per share)	$ 1.05	$ 0.63	$ (0.53)	$ (0.64)	$ 0.45	$ 0.43	$ 0.38	$ 0.21	$ 0.45	$ 1.42	$ (0.83)