Cohen & Steers (CNS) 10-Q 10 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - shares	3 Months Ended
	Mar. 31, 2018	May 01, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	COHEN & STEERS INC
Entity Central Index Key	1,284,812
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		46,747,310

Condensed Consolidated Statemen

Condensed Consolidated Statements of Financial Condition (Unaudited) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents		$ 168,644	$ 193,452
Investments ($529 and $414) (1) ($99,811 and $68,101) (2)	[1],[2]	139,435	108,106
Accounts receivable		63,016	53,854
Due from brokers ($9,593 and $5,410) (2)	[1]	11,790	6,429
Property and equipment—net		14,939	15,040
Goodwill and intangible assets—net		20,625	20,379
Deferred income tax asset—net		1,794	5,812
Other assets ($1,773 and $931)	[1]	8,698	7,053
Total assets		428,941	410,125
Liabilities:
Accrued compensation		10,156	41,370
Distribution and service fees payable		6,774	6,231
Income tax payable		23,001	19,892
Due to broker ($7,107 and $3,203)	[1]	7,137	3,282
Deferred rent		5,934	5,994
Other liabilities and accrued expenses ($338 and $291)	[1]	10,492	10,025
Total liabilities		63,494	86,794
Commitments and contingencies
Redeemable noncontrolling interest		81,604	47,795
Stockholders’ equity:
Common stock, $0.01 par value; 500,000,000 shares authorized; 51,793,732 and 51,104,593 shares issued at March 31, 2018 and December 31, 2017, respectively		518	511
Additional paid-in capital		577,169	570,486
Accumulated deficit		(125,293)	(137,972)
Accumulated other comprehensive loss, net of tax		(4,228)	(3,671)
Less: Treasury stock, at cost, 5,048,878 and 4,789,608 shares at March 31, 2018 and December 31, 2017, respectively		(164,323)	(153,818)
Total stockholders’ equity		283,843	275,536
Total liabilities and stockholders’ equity		$ 428,941	$ 410,125
[1]	Asset and liability amounts in parentheses represent the aggregated balances at March 31, 2018 and December 31, 2017 attributable to the Cohen & Steers SICAV Global Listed Infrastructure Fund, the Cohen & Steers Co-Investment Partnership, L.P. and the Cohen & Steers SICAV Global Preferred Securities Fund, respectively.
[2]	Pledged as collateral attributable to the consolidated balances of the Cohen & Steers Active Commodities Strategy Fund, Inc. at March 31, 2018 and December 31, 2017, respectively.

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Financial Condition (Unaudited) (Parenthetical) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Common stock, par value		$ 0.01	$ 0.01
Common stock, shares authorized		500,000,000	500,000,000
Common stock, shares issued		51,793,732	51,104,593
Treasury stock, shares		5,048,878	4,789,608
Investments		$ 43,615	$ 74,856
Due from broker	[1]	11,790	6,429
Other Assets	[1]	8,698	7,053
Due to broker	[1]	7,137	3,282
Other liabilities and accrued expenses	[1]	10,492	10,025
GLI SICAV, GRP-CIP and SICAV Preferred
Investments		99,811	68,101
Due from broker		9,593	5,410
Other Assets		1,773	931
Due to broker		7,107	3,203
Other liabilities and accrued expenses		$ 338	$ 291
[1]	Asset and liability amounts in parentheses represent the aggregated balances at March 31, 2018 and December 31, 2017 attributable to the Cohen & Steers SICAV Global Listed Infrastructure Fund, the Cohen & Steers Co-Investment Partnership, L.P. and the Cohen & Steers SICAV Global Preferred Securities Fund, respectively.

Condensed Consolidated Stateme4

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue:
Investment advisory and administration fees	$ 84,434	$ 79,608
Distribution and service fees	7,400	7,396
Portfolio consulting and other	2,630	2,737
Total revenue	94,464	89,741
Expenses:
Employee compensation and benefits	31,156	29,383
Distribution and service fees	12,842	13,163
General and administrative	12,185	10,556
Depreciation and amortization	1,062	1,111
Total expenses	57,245	54,213
Operating income	37,219	35,528
Non-operating income:
Interest and dividend income—net	1,801	499
Gain (loss) from trading investments—net		273
Gain (Loss) on Investments	(4,502)	19
Other gains (losses)	2,502	(291)
Total non-operating income (loss)	(199)	227
Income before provision for income taxes	37,020	35,755
Provision for income taxes	8,096	12,811
Net income	28,924	22,944
Less: Net (income) loss attributable to redeemable noncontrolling interest	(1,338)	41
Net income attributable to common stockholders	$ 27,586	$ 22,985
Earnings per share attributable to common stockholders:
Basic (in dollars per share)	$ 0.59	$ 0.50
Diluted (in dollars per share)	0.59	0.49
Dividends declared per share (in dollars per share)	$ 0.33	$ 0.28
Weighted average shares outstanding:
Basic (shares)	46,683	46,243
Diluted (shares)	47,152	46,603

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 28,924	$ 22,944
Less: Net (income) loss attributable to redeemable noncontrolling interest	(1,338)	41
Net income attributable to common stockholders	27,586	22,985
Foreign currency translation income (loss)	538	487
Net unrealized gain (loss) from available-for-sale investments	0	414
Reclassification to statements of operations of (gain) loss from available-for-sale investments	0	(35)
Other comprehensive income (loss)	538	866
Total comprehensive income attributable to common stockholders	$ 28,124	$ 23,851

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Changes in Stockholders' Equity and Redeemable Noncontrolling Interest (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stocks	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss), Net of Tax	Treasury Stock	Total Stockholders' Equity	Redeemable Noncontrolling Interest
Beginning balance at Dec. 31, 2016		$ 504	$ 543,829	$ (127,957)	$ (5,885)	$ (144,677)	$ 265,814
Beginning balance (redeemable noncontrolling interest) at Dec. 31, 2016								$ 853
Beginning balance (shares of common stock, net) at Dec. 31, 2016		45,890
Dividends				(13,406)			(13,406)
Issuance of common stock		$ 7	250				257
Issuance of common stock, shares		664
Repurchase of common stock						(9,040)	(9,040)
Repurchase of common stock, shares		(262)
Issuance of restricted stock units			596				596
Amortization of restricted stock units—net			5,578	(285)			5,293
Forfeitures of restricted stock units			(4)				(4)
Net income (loss)	$ 22,944			22,985			22,985	(41)
Other comprehensive income (loss), net of tax	866				866		866
Contributions from redeemable noncontrolling interest	174							174
Distributions to redeemable noncontrolling interest								(11)
Ending balance at Mar. 31, 2017		$ 511	550,249	(118,663)	(5,019)	(153,717)	273,361
Ending balance (redeemable noncontrolling interest) at Mar. 31, 2017								975
Ending balance (shares of common stock, net) at Mar. 31, 2017		46,292
Cumulative-effect adjustment due to the adoption of the new financial instruments accounting standard				1,095	(1,095)
Beginning balance at Dec. 31, 2017	275,536	$ 511	570,486	(137,972)	(3,671)	(153,818)	275,536
Beginning balance (redeemable noncontrolling interest) at Dec. 31, 2017								47,795
Beginning balance (shares of common stock, net) at Dec. 31, 2017		46,315
Dividends				(16,002)			(16,002)
Issuance of common stock		$ 7	250				257
Issuance of common stock, shares		689
Repurchase of common stock						(10,505)	(10,505)
Repurchase of common stock, shares		(259)
Issuance of restricted stock units			733				733
Amortization of restricted stock units—net			5,700				5,700
Forfeitures of restricted stock units							0
Net income (loss)	28,924			27,586			27,586	1,338
Other comprehensive income (loss), net of tax	538				538		538
Contributions from redeemable noncontrolling interest	34,423							34,423
Distributions to redeemable noncontrolling interest								(1,952)
Ending balance at Mar. 31, 2018	$ 283,843	$ 518	$ 577,169	$ (125,293)	$ (4,228)	$ (164,323)	$ 283,843
Ending balance (redeemable noncontrolling interest) at Mar. 31, 2018								$ 81,604
Ending balance (shares of common stock, net) at Mar. 31, 2018		46,745

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 28,924	$ 22,944
Adjustments to reconcile net income to net cash used in operating activities:
Stock compensation expense	5,738	5,328
Amortization of deferred commissions	473	954
Depreciation and amortization	1,062	1,111
Deferred rent	(60)	(57)
Gain (Loss) on Investments	(4,502)	19
Deferred income taxes	3,988	5,406
Foreign currency (gain) losses	(1,136)	1,452
Changes in operating assets and liabilities:
Accounts receivable	(8,026)	(13,840)
Due from broker	(5,361)	(580)
Deferred commissions	(348)	(443)
Trading investments	(34,057)	(2,200)
Other assets	(1,737)	(44)
Accrued compensation	(31,188)	(25,770)
Distribution and service fees payable	543	(4)
Due to broker	3,855	0
Income tax payable	3,109	6,531
Other liabilities and accrued expenses	647	(2,581)
Net cash provided by (used in) operating activities	(29,072)	(1,812)
Cash flows from investing activities:
Proceeds from redemptions of equity method investments—net	26	0
Payments to Acquire Marketable Securities	3,856	9,545
Proceeds from Sale, Maturity and Collection of Investments	1,993	6,746
Purchases of property and equipment	(906)	(649)
Net cash provided by (used in) investing activities	(2,743)	(3,448)
Cash flows from financing activities:
Issuance of common stock	219	219
Repurchase of common stock	(10,505)	(9,040)
Dividends to stockholders	(15,445)	(12,979)
Distributions to redeemable noncontrolling interest	(1,952)	(11)
Contributions from redeemable noncontrolling interest	34,423	174
Net cash provided by (used in) financing activities	6,740	(21,637)
Net decrease in cash and cash equivalents	(25,075)	(26,897)
Effect of foreign exchange rate changes on cash and cash equivalents	267	$ 348
Cash and cash equivalents, beginning of the period	193,452
Cash and cash equivalents, end of the period	$ 168,644

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Cash Flows (Unaudited) (Supplemental Disclosures of Cash Flow Information) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Cash Flows [Abstract]
Income taxes paid, net	$ 1,144	$ (989)
Fully vested restricted stock units issued	176	168
Restricted stock unit dividend equivalents, net of forfeitures	$ 557	$ 427

Organization and Description of

Organization and Description of Business	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business Cohen & Steers, Inc. (CNS) was organized as a Delaware corporation on March 17, 2004. CNS is the holding company for its direct and indirect subsidiaries, including Cohen & Steers Capital Management, Inc. (CSCM), Cohen & Steers Securities, LLC (CSS), Cohen & Steers Asia Limited (CSAL), Cohen & Steers UK Limited (CSUK) and Cohen & Steers Japan, LLC (collectively, the Company). The Company is a global investment manager specializing in liquid real assets, including real estate securities, listed infrastructure, commodities and natural resource equities, as well as preferred securities and other income solutions. Founded in 1986, the Company is headquartered in New York City, with offices in London, Hong Kong, Tokyo and Seattle.

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	Basis of Presentation and Significant Accounting Policies The condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). The condensed consolidated financial statements set forth herein include the accounts of CNS and its direct and indirect subsidiaries. Intercompany balances and transactions have been eliminated in consolidation. The condensed consolidated financial statements of the Company included herein are unaudited and have been prepared in accordance with the instructions to Form 10-Q pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). In the opinion of management, all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation of the interim results have been made. The Company's condensed consolidated financial statements and the related notes should be read together with the consolidated financial statements and the related notes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2017 . The Company reclassified certain prior period amounts in the condensed consolidated financial statements to conform with the current period presentation. Recently Adopted Accounting Pronouncements —In May 2017, the FASB issued new guidance for modification accounting related to share-based payment transactions in order to provide clarity and to reduce current diversity in practice. This new guidance does not fundamentally change the notion of a modification. Instead, the amendments clarify which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. The amendments became effective on January 1, 2018 and required prospective application. The Company's adoption of the new guidance did not have a material effect on its condensed consolidated financial statements and related disclosures. In August 2016, the FASB amended the current guidance on the classification of certain cash receipts and payments in the statement of cash flows. This guidance is intended to unify the currently diverse presentations and classifications, including debt prepayment or debt extinguishment costs, settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies, distributions received from equity method investees, beneficial interests in securitization transactions, and separately identifiable cash flows and application of the predominance principle. The Company evaluated the eight issues and concluded that only distributions received from equity method investees is applicable to the Company. This amended guidance became effective on January 1, 2018 and was adopted retrospectively. The Company made an accounting policy election to use the Cumulative Earnings Approach when determining whether distributions received from equity method investments should be classified as either operating or investing activities within its condensed consolidated statements of cash flows. The Company's adoption and application of the new guidance did not have a material effect on its condensed consolidated financial statements and related disclosures. In January 2016, the FASB issued new guidance amending the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. In addition, the FASB clarified guidance related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale debt securities. This new guidance became effective on January 1, 2018 and required the Company to recognize a cumulative-effect adjustment to the beginning retained earnings of approximately $1,095,000 , net of tax. Furthermore, changes in the fair value of the Company’s equity investments carried at fair value are now reported through earnings rather than through other comprehensive income. Additionally, due to the required cumulative-effect method of adoption applied, certain disclosures for prior periods have not been recast to conform with the current period presentation. Lastly, upon adoption of the new guidance, the Company reclassified certain investments previously classified as available-for-sale to trading investments or equity investments at fair value. See Notes 4 and 5 for further discussion about the Company's investments. In May 2014, the FASB issued new guidance which outlined a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. The core principle of the revenue model is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The FASB issued a number of amendments and revisions to the new standard in order to provide more detailed guidance and clarifications. This new guidance became effective on January 1, 2018 and the Company elected to adopt the standard using the retrospective method, which required the recasting of prior period amounts. The adoption of the new standard did not have a material impact on the timing of recognition for the Company's revenue but did affect the presentation of certain revenue and expenses on either a gross or net basis. The adoption of the new revenue recognition standard resulted in the following changes to the Company's previously reported results for the three months ended March 31, 2017 (in thousands): As Previously Reported Net Adjustments Due to New Revenue Standard As Recasted Revenue: Investment advisory and administration fees $ 81,903 $ (2,295 ) $ 79,608 Distribution and service fees 5,046 2,350 7,396 Total $ 86,949 $ 55 $ 87,004 Expenses: Distribution and service fees $ 9,780 $ 2,429 $ 12,209 General and administrative 12,930 (2,374 ) 10,556 Total $ 22,710 $ 55 $ 22,765 Accounting Estimates —The preparation of the condensed consolidated financial statements in conformity with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the dates of the condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting periods. Management believes the estimates used in preparing the condensed consolidated financial statements are reasonable and prudent. Actual results could differ from those estimates. Consolidation of Company-sponsored Funds —Investments in Company-sponsored funds and management fees are evaluated at inception and thereafter, if there is a reconsideration event, in order to determine whether to apply the Variable Interest Entity (VIE) model or the Voting Interest Entity (VOE) model. In performing this analysis, all of the Company's management fees are presumed to be commensurate and at market and are therefore not considered variable interests. A VIE is an entity in which either (i) the equity investment at risk is not sufficient to permit the entity to finance its own activities without additional financial support or (ii) the group of holders of the equity investment at risk lack certain characteristics of a controlling financial interest. The primary beneficiary is the entity that has (i) the power to direct the activities of the VIE that most significantly affect its performance and (i) the obligation to absorb losses of the entity or the right to receive benefits from the entity that could potentially be significant to the VIE. Investments and redemptions or amendments to the governing documents of the respective entities could affect an entity's status as a VIE or the determination of the primary beneficiary. The Company assesses whether it is the primary beneficiary of any VIEs identified by evaluating its economic interests in the entity held either directly by the Company and its affiliates or indirectly through employees. VIEs for which the Company is deemed to be the primary beneficiary are consolidated. Investments in Company-sponsored funds that are determined to be VOEs are consolidated when the Company's ownership interest is greater than 50% of the outstanding voting interests of the fund or when the Company is the general partner of the fund and the limited partners do not have substantive kick-out or participating rights in the fund. The Company records noncontrolling interests in consolidated funds for which the Company's ownership is less than 100 %. Cash and Cash Equivalents —Cash and cash equivalents are on deposit with three major financial institutions and consist of short-term, highly-liquid investments, which are readily convertible into cash and have original maturities of three months or less. Due from/to Brokers —Company-sponsored funds that are consolidated transact with brokers for certain investment activities. The clearing and custody operations for these investment activities are performed pursuant to contractual agreements. The due from/to brokers balance represents cash and cash equivalents balances at brokers/custodians and/or receivables and payables for unsettled securities transactions. Investments —Management of the Company determines the appropriate classification of its investments at the time of purchase and re-evaluates such determination on an ongoing basis and at each statement of financial condition date. At March 31, 2018 , the Company's investments were comprised of equity investments at fair value, trading investments and equity method investments. Realized and unrealized gains and losses on equity investments at fair value, trading investments and equity method investments are recorded in gain (loss) from investments—net in the Company's condensed consolidated statements of operations. Investments classified as equity method investments represent seed investments in which the Company owns between 20 - 50% of the outstanding voting interests in the affiliated fund or when it is determined that the Company is able to exercise significant influence but not control over the investments. When using the equity method, the Company recognizes its respective share of the affiliated investee fund net income or loss for the period which is recorded as gain (loss) from investments—net in the Company's condensed consolidated statements of operations. At March 31, 2018 , the Company's equity method investment consisted of an interest in a Company-sponsored limited partnership which measures its underlying investments at fair value based on quoted market prices or NAV (or its equivalent) as a practical expedient and reports a net asset value on a recurring basis. The carrying amount of this investment approximated its fair value. From time to time, the affiliated funds consolidated by the Company enter into derivative contracts to gain exposure to the underlying commodities markets or to hedge market and credit risks of the underlying portfolios utilizing options and futures contracts. These instruments are measured at fair value based on their settlement price at the close of trading on the associated commodities exchange or board of trade with gains and losses recorded as gain (loss) from investments—net in the Company's condensed consolidated statements of operations. The fair values of these instruments are recorded in other assets or other liabilities and accrued expenses on the Company's condensed consolidated statements of financial condition. At March 31, 2018 , none of the outstanding derivative contracts were subject to a master netting agreement or other similar arrangement. Additionally, from time to time, the Company enters into foreign exchange contracts to hedge its currency exposure related to certain client receivables. These instruments are measured at fair value with gains and losses recorded in other non-operating income (loss) in the Company's condensed consolidated statements of operations. The fair values of these contracts are recorded in other assets or other liabilities and accrued expenses on the Company's condensed consolidated statements of financial condition. Goodwill and Intangible Assets —Goodwill represents the excess of the cost of the Company's investment in the net assets of an acquired company over the fair value of the underlying identifiable net assets at the date of acquisition. Goodwill and indefinite-lived intangible assets are not amortized but are tested at least annually for impairment by comparing the fair value to their carrying amounts. Finite-lived intangible assets are amortized over their useful lives and are tested for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. Redeemable Noncontrolling Interest —Redeemable noncontrolling interest represents third-party interests in the Company's consolidated funds. This interest is redeemable at the option of the investors and therefore is not treated as permanent equity. Redeemable noncontrolling interest is remeasured at redemption value which approximates the fair value at each reporting period. Investment Advisory and Administration Fees —The Company earns revenue by providing asset management services to institutional accounts and to Company-sponsored open-end and closed-end funds. Investment advisory fees are earned pursuant to the terms of investment management agreements and are based on a contractual fee rate applied to the average assets in the portfolio. The Company also earns administration fees from certain Company-sponsored open-end and closed-end funds pursuant to the terms of underlying administration contracts. Administration fees are based on the average assets under management of such funds. Investment advisory and administration fee revenue is recognized when earned and is recorded net of any fund reimbursements. The investment advisory and administration contracts each include a single performance obligation as the services provided are not separately identifiable and, therefore, is accounted for as a series satisfied over time using a time-based method (days elapsed). Additionally, investment advisory and administration fees represent variable consideration, as fees are based on average assets under management which fluctuate due to changes in the financial markets. Distribution and Service Fee Revenue —Distribution and service fee revenue is based on the average daily net assets of certain share classes of the Company's sponsored open-end funds distributed by CSS. Distribution fee agreements include a single performance obligation that is satisfied at a point in time when an investor purchases shares in a Company-sponsored open-end fund. Distribution fees represent variable consideration, as fees are based on average assets under management which fluctuate due to changes in the financial markets. For both the three months ended March 31, 2018 and 2017, a portion of the distribution fee revenue recognized in the current period may relate to performance obligations satisfied (or partially satisfied) in prior periods. Service fee agreements include a single performance obligation as the services provided are not separately identifiable and, therefore, is accounted for as a series satisfied over time using a time-based method (days elapsed). Service fees represent variable consideration, as fees are based on average assets under management which fluctuate due to changes in the financial markets. Portfolio Consulting and Other —The Company earns portfolio consulting and other fees by (i) providing portfolio consulting services in connection with model-based strategy accounts, (ii) earning a licensing fee for the use of the Company's proprietary indexes and (iii) providing portfolio monitoring services related to a number of unit investment trusts. Revenue is earned pursuant to the terms of the underlying contracts and the fee schedules for these relationships vary based on the type of services the Company provides for each relationship. The majority of the Company's revenue from portfolio consulting and other is recognized over time and represents variable consideration, as fees are based on average assets under advisement which fluctuate due to changes in the financial markets. Commission income and contingent deferred sales charge (CDSC) fees, which are earned pursuant to specific transactions such as a purchase or sale of fund shares, are recognized at a point in time. Distribution and Service Fee Expense —Distribution and service fee expense includes distribution fees, shareholder servicing fees and intermediary assistance payments. Distribution and service fee expense is recorded on an accrual basis. Distribution fee expense represents payments made to qualified intermediaries for (i) assistance in connection with the distribution of the Company's sponsored open-end funds' shares and (ii) for other expenses such as advertising costs and printing and distribution of prospectuses to investors. Such amounts may also be used to pay financial intermediaries for services as specified in the terms of written agreements complying with Rule 12b-1 of the Investment Company Act of 1940 (Rule 12b-1). The Company pays distribution fee expense based on the average daily net assets under management of certain share classes of certain of the funds. Shareholder servicing fee expense represents payments made to qualified intermediaries for shareholder account service and maintenance. These services are provided pursuant to written agreements with such qualified institutions. The Company pays shareholder servicing fee expense generally based on the average assets under management or the number of accounts being serviced. The Company previously recognized certain distribution and service fee revenue and expense on a net basis; however, upon adoption of the new revenue guidance, the Company recognizes such revenue and expense on a gross basis. Intermediary assistance payments represent payments to qualified intermediaries for activities related to distribution, shareholder servicing and marketing and support of the Company's sponsored open-end funds and are incremental to those described above. Intermediary assistance payments are generally based on the average assets under management or the number of accounts being serviced. Stock-based Compensation —The Company recognizes compensation expense for the grant-date fair value of awards of equity instruments to employees. This expense is recognized over the period during which employees are required to provide service. Forfeitures are recorded as incurred. Income Taxes —The Company records the current and deferred tax consequences of all transactions that have been recognized in the condensed consolidated financial statements in accordance with the provisions of the enacted tax laws. Deferred tax assets are recognized for temporary differences that will result in deductible amounts in future years at tax rates that are expected to apply in those years. Deferred tax liabilities are recognized for temporary differences that will result in taxable income in future years at tax rates that are expected to apply in those years. The Company records a valuation allowance, when necessary, to reduce deferred tax assets to an amount that more likely than not will be realized. The effective tax rate for interim periods represents the Company's best estimate of the effective tax rate expected to be applied to the full fiscal year. The calculation of tax liabilities involves dealing with uncertainties in the application of complex tax laws and regulations in a multitude of jurisdictions across the Company's global operations. A tax benefit from an uncertain tax position may be recognized when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, on the basis of the technical merits. The Company records potential interest and penalties related to uncertain tax positions in the provision for income taxes in the condensed consolidated statements of operations. Currency Translation and Transactions —Assets and liabilities of subsidiaries having non-U.S. dollar functional currencies are translated at exchange rates at the applicable condensed consolidated statement of financial condition date. Revenue and expenses of such subsidiaries are translated at average exchange rates during the period. The gains or losses resulting from translating non-U.S. dollar functional currency into U.S. dollars are included in the Company's condensed consolidated statements of comprehensive income. The cumulative translation adjustment was $(4,228,000) and $(4,781,000) at March 31, 2018 and December 31, 2017 , respectively. Gains or losses resulting from non-U.S. dollar currency transactions are included in other non-operating income (loss) in the condensed consolidated statements of operations. Comprehensive Income —The Company reports all changes in comprehensive income in the condensed consolidated statements of comprehensive income. Comprehensive income includes net income or loss attributable to common stockholders and amounts attributable to foreign currency translation gain (loss), net of tax. Recently Issued Accounting Pronouncements —In February 2018, the FASB issued new guidance allowing entities to reclassify certain tax effects related to the enactment of the Tax Cuts and Jobs Act (the Tax Act) from accumulated other comprehensive income (AOCI) to retained earnings. Prior to the issuance of the new guidance, a portion of the previously recognized deferred tax effects recorded in AOCI was "left stranded" in AOCI as the effect of remeasuring the deferred taxes using the reduced federal corporate income tax rate was required to be recorded through income. The new guidance allows these stranded tax effects to be reclassified from AOCI to retained earnings. The new guidance will be effective on January 1, 2019, with early adoption permitted and is to be applied either in the period of adoption or retrospectively to each period in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Act is recognized. The Company is still assessing which adoption method it will choose but it does not expect either method to have a material effect on its condensed consolidated financial statements and related disclosures. In August 2017, the FASB issued new guidance amending the accounting for hedging activities. The new guidance (i) expands hedge accounting for nonfinancial and financial risk components and amends measurement methodologies to more closely align hedge accounting with an entity's risk management activities, (ii) decreases the complexity of preparing and understanding hedge results through eliminating the separate measurement and reporting of hedge ineffectiveness, (iii) enhances transparency, comparability and understandability of hedge results through enhanced disclosures and changing the presentation of hedge results to align the effects of the hedging instrument and the hedged item and (iv) reduces the cost and complexity of applying hedge accounting by simplifying the manner in which assessments of hedge effectiveness may be performed. The new guidance will be effective on January 1, 2019, with early adoption permitted. The Company does not expect the adoption of the new guidance to have a material effect on its condensed consolidated financial statements and related disclosures. In January 2017, the FASB issued guidance to simplify the goodwill impairment test by removing the requirement to perform a hypothetical purchase price allocation. A goodwill impairment will now be the amount by which a reporting unit's carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. This new guidance will be effective on January 1, 2020. The Company does not expect the adoption of the new guidance to have a material effect on its condensed consolidated financial statements and related disclosures. In February 2016, the FASB issued guidance introducing a new lease model which requires lessees to recognize leases on-balance sheet and disclose key information about leasing arrangements. The new guidance establishes a right-of-use model (ROU) that requires a lessee to recognize an ROU asset and lease liability on the balance sheet for all leases with a term longer than 12 months. Leases will be classified as finance or operating, with classification affecting the pattern and classification of expense recognition in the income statement. The new guidance also requires disclosures by lessees and lessors to enable users of financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. The new guidance is effective on January 1, 2019, with early adoption permitted. The Company expects to adopt the new guidance on its effective date. A modified retrospective transition approach is required for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. While the Company is continuing to assess the effect of adoption, it currently believes the most significant change relates to the recognition of new ROU assets and lease liabilities on its condensed consolidated statements of financial condition for its office space and other operating leases. The Company does not expect a significant change in its leasing activity between now and adoption. The Company is still assessing which of the available practical expedients it plans to elect upon adoption.

Revenue Revenue

Revenue Revenue	3 Months Ended
	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue	Revenue The following tables summarize revenue recognized from contracts with customers by client domicile and revenue by vehicle for all periods presented (in thousands): Three Months Ended 2018 2017 Client domicile: North America $ 79,707 $ 73,380 Japan 9,093 11,125 Asia excluding Japan 3,035 2,647 Europe 2,629 2,589 Total $ 94,464 $ 89,741 Three Months Ended 2018 2017 Vehicle: Open-end funds (1) $ 47,452 $ 43,954 Closed-end funds 19,177 18,880 Institutional accounts 25,205 24,170 Portfolio consulting and other 2,630 2,737 Total $ 94,464 $ 89,741 ________________________ (1) Included distribution and service fees of $7.4 million for both the three months ended March 31, 2018 and 2017.

Investments

Investments	3 Months Ended
	Mar. 31, 2018
Investments [Abstract]
Investments	Investments The following tables summarize the Company's investments for the periods presented (in thousands): March 31, 2018 Equity investments at fair value $ 43,615 Trading investments 95,785 Equity method investments 35 Total investments $ 139,435 December 31, 2017 Trading investments $ 74,856 Equity method investments 6,176 Available-for-sale investments 27,074 Total investments $ 108,106 Equity investments at fair value —represents equity investments held within the affiliated funds that the Company consolidates, individual investments held directly for the purposes of establishing performance track records and seed investments in Company-sponsored funds. These investments include equity securities, investment-grade preferred instruments and investments in Company-sponsored open-end funds where the Company has neither control nor the ability to exercise significant influence. Investments in equity securities are measured at fair value generally based on quoted market prices, market prices obtained from independent pricing services engaged by management or as determined by management and approved by the Company's valuation committee. Trading investments —represents fixed income investments held within the affiliated funds that the Company consolidates and individual fixed income investments held directly for the purposes of establishing performance track records. Fixed income investments are carried at fair value based on quoted market prices or market prices obtained from independent pricing services engaged by management. Equity method investments —represents an interest in a Company-sponsored limited partnership measured at NAV (or its equivalent) as a practical expedient reported on a recurring basis. The carrying amount of this investment approximated its fair value. The Company seeded one new fund during the three months ended March 31, 2017. The following tables summarize gain (loss) from investments for the for the periods presented (in thousands): Three Months Ended March 31, 2018 Gain (loss) from investments—net (1) Net realized gains (losses) during the period $ 155 Net unrealized gains (losses) during the period on investments still held at the end of the period (4,657 ) Gain (loss) from investments—net $ (4,502 ) ________________________ (1) Includes net income (loss) attributable to redeemable noncontrolling interest. Three Months Ended March 31, 2017 Gain (loss) from trading investments—net (1) $ 273 Equity in earnings (losses) of affiliates—net (289 ) Gain (loss) from available-for-sale investments—net 35 Total gain (loss) from investments $ 19 _________________________ (1) Includes net income (loss) attributable to redeemable noncontrolling interest. The following tables summarize the condensed consolidated statements of financial condition attributable to the Company's consolidated VIEs, which included the Cohen & Steers SICAV Global Listed Infrastructure Fund (GLI SICAV), the Cohen & Steers Co-Investment Partnership, L.P. (GRP-CIP) and the Cohen & Steers SICAV Global Preferred Securities Fund (SICAV Preferred) for the periods presented (in thousands): March 31, 2018 GLI SICAV GRP-CIP SICAV Preferred Total Assets (1) Investments $ 5,648 $ 723 $ 93,440 $ 99,811 Due from brokers 190 191 9,212 9,593 Other assets 186 — 1,587 1,773 Total assets $ 6,024 $ 914 $ 104,239 $ 111,177 Liabilities (1) Due to brokers $ 50 $ — $ 7,057 $ 7,107 Other liabilities and accrued expenses 99 5 234 338 Total liabilities $ 149 $ 5 $ 7,291 $ 7,445 December 31, 2017 GLI SICAV GRP-CIP SICAV Preferred Total Assets (1) Investments $ 5,961 $ 1,330 $ 60,810 $ 68,101 Due from brokers 285 202 4,923 5,410 Other assets 32 — 899 931 Total assets $ 6,278 $ 1,532 $ 66,632 $ 74,442 Liabilities (1) Due to brokers $ 35 $ — $ 3,168 $ 3,203 Other liabilities and accrued expenses 87 5 199 291 Total liabilities $ 122 $ 5 $ 3,367 $ 3,494 _________________________ (1) The assets may only be used to settle obligations of each VIE and the liabilities are the sole obligation of each VIE, for which creditors do not have recourse to the general credit of the Company. The following table summarizes the cost, gross unrealized gains, gross unrealized losses and fair value of available-for-sale investments at December 31, 2017 (in thousands): December 31, 2017 Cost Gross Unrealized Gains Gross (1) Fair Value Common stocks $ 6,782 $ 639 $ (183 ) $ 7,238 Company-sponsored funds 13,376 1,269 (13 ) 14,632 Fixed income 3,966 15 (20 ) 3,961 Preferred securities 1,100 29 (5 ) 1,124 Other 100 19 — 119 Total available-for-sale investments $ 25,324 $ 1,971 $ (221 ) $ 27,074 _________________________ (1) At December 31, 2017 , there were no investments with material unrealized losses continuously for a period of more than 12 months. Available-for-sale investments with a fair value of approximately $6,086,000 at December 31, 2017 were in an unrealized loss position. At December 31, 2017 , unrealized losses on available-for-sale investments were generally caused by changes in market conditions. When evaluating whether an unrealized loss on an available-for-sale investment is other than temporary, the Company reviews such factors as the extent and duration of the loss as well as qualitative and quantitative information about the financial condition and near-term prospects of the issuers. Furthermore, the Company determined that it had the ability and intent to hold the remaining available-for-sale investments for which no other-than-temporary impairment has occurred until a recovery of fair value. Accordingly, impairment of these investments, if any, was considered temporary. The following table summarizes sales proceeds, gross realized gains and losses from available-for-sale investments for the three months ended March 31, 2017 (in thousands): Three Months Ended March 31, 2017 Proceeds from sales $ 6,886 Gross realized gains 98 Gross realized losses (63 )

Fair Value

Fair Value	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value	Fair Value Accounting Standards Codification Topic 820, Fair Value Measurement (ASC 820) specifies a hierarchy of valuation classifications based on whether the inputs to the valuation techniques used in each valuation classification are observable or unobservable. These classifications are summarized in the three broad levels listed below: • Level 1—Unadjusted quoted prices for identical instruments in active markets. • Level 2—Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs and significant value drivers are observable. • Level 3—Valuations derived from valuation techniques in which significant inputs or significant value drivers are unobservable. Inputs used to measure fair value might fall in different levels of the fair value hierarchy, in which case the Company defaults to the lowest level input that is significant to the fair value measurement in its entirety. These levels are not necessarily an indication of the risk or liquidity associated with the investments. In determining the appropriate levels, the Company performed a detailed analysis of the assets and liabilities that are subject to ASC 820. Transfers among levels, if any, are recorded at the end of the reporting period. There were no transfers between level 1 and level 2 during the period ended March 31, 2018 . The following table presents fair value measurements at March 31, 2018 (in thousands): Level 1 Level 2 Level 3 Investments Measured at NAV Total Cash equivalents $ 159,008 $ — $ — $ — $ 159,008 Equity investments at fair value Common stocks $ 13,668 $ — $ — $ — $ 13,668 Company-sponsored funds 14,063 — — — 14,063 Limited partnership interests 623 — — 723 1,346 Preferred securities 13,883 546 — — 14,429 Other — — — 109 109 Total $ 42,237 $ 546 $ — $ 832 $ 43,615 Trading investments Fixed income $ 3,966 $ 91,819 $ — $ — $ 95,785 Total $ 3,966 $ 91,819 $ — $ — $ 95,785 Equity method investments $ — $ — $ — $ 35 $ 35 Total investments $ 46,203 $ 92,365 $ — $ 867 $ 139,435 Derivatives - assets Commodity contracts $ 920 $ — $ — $ — $ 920 Foreign exchange contracts — — — — — Total $ 920 $ — $ — $ — $ 920 Derivatives - liabilities Commodity contracts $ 782 $ — $ — $ — $ 782 Foreign exchange contracts — 910 — — 910 Total $ 782 $ 910 $ — $ — $ 1,692 Cash equivalents were comprised of investments in actively traded U.S. Treasury money market funds measured at NAV. Investments measured at NAV were comprised of certain investments measured at fair value using NAV (or its equivalent) as a practical expedient. These investments have not been classified in the fair value hierarchy. The fair value amounts presented in the above table are intended to permit reconciliation of the fair value hierarchy to the amounts presented on the condensed consolidated statement of financial position. Equity investments at fair value classified as level 2 were comprised of certain preferred securities with predominately equity-like characteristics whose fair values are generally determined using third-party pricing services. The pricing services may utilize pricing models, and inputs into those models may include reported trades, executable bid and ask prices, broker-dealer quotations, prices or yields of similar securities, benchmark curves and other market information. The pricing services may use a matrix approach, which considers information regarding securities with similar characteristics to determine the valuation for a security. Equity investments at fair value classified as investments measured at NAV (or its equivalent) as a practical expedient in the above table were comprised of: • Limited partnership interests in limited partnership vehicles that invest in non-registered real estate funds, which are valued based on the NAVs of the underlying funds. At March 31, 2018 , the Company did not have the ability to redeem these interests. • The Company's co-investment in a Cayman trust invested in global listed infrastructure securities. At March 31, 2018 , there were no contractual restrictions on the Company's ability to redeem its interest. Trading investments classified as level 2 in the above table were comprised of U.S. Treasury Bills carried at amortized cost, which approximates fair value, corporate debt securities, as well as certain preferred securities with predominately debt-like characteristics. The fair value amounts were generally determined using third-party pricing services. The pricing services may utilize evaluated pricing models that vary by asset class and incorporate available trade, bid and other market information. Since these securities do not trade on a daily basis, the pricing services evaluate pricing applications and apply available information through processes such as yield curves, benchmarking of like securities, sector groupings, and matrix pricing, to prepare evaluations. Equity method investments classified as investments measured at NAV (or its equivalent) as a practical expedient in the above table were comprised of the Company's partnership interest in a Company-sponsored limited partnership that invests in non-registered real estate funds, which approximated its fair value based on the fund's NAV. At March 31, 2018 , the Company's ownership in this limited partnership was approximately 0.2% . The Company's risk with respect to this investment is limited to its equity ownership and any uncollected management fees. At March 31, 2018 , the Company did not have the ability to redeem this investment. The following table presents fair value measurements at December 31, 2017 (in thousands): Level 1 Level 2 Level 3 Investments Measured at NAV Total Cash equivalents $ 173,270 $ — $ — $ — $ 173,270 Trading investments Common stocks $ 5,961 $ — $ — $ — $ 5,961 Fixed income — 6,755 — — 6,755 Limited partnership interests — — 605 725 1,330 Preferred securities 7,658 53,152 — — 60,810 Total $ 13,619 $ 59,907 $ 605 $ 725 $ 74,856 Equity method investments $ — $ — $ — $ 6,176 $ 6,176 Available-for-sale investments Common stocks $ 7,238 $ — $ — $ — $ 7,238 Company-sponsored funds 14,632 — — — 14,632 Fixed income — 3,961 — — 3,961 Preferred securities 999 125 — — 1,124 Other — — — 119 119 Total $ 22,869 $ 4,086 $ — $ 119 $ 27,074 Total investments $ 36,488 $ 63,993 $ 605 $ 7,020 $ 108,106 Derivatives - assets Commodity contracts 487 — — — 487 Foreign exchange contracts — — — — — Total $ 487 $ — $ — $ — $ 487 Derivatives - liabilities Commodity contracts $ 286 $ — $ — $ — $ 286 Foreign exchange contracts — 64 — — 64 Total $ 286 $ 64 $ — $ — $ 350 Cash equivalents were comprised of investments in actively traded U.S. Treasury money market funds measured at NAV. Investments measured at NAV were comprised of certain investments measured at fair value using NAV (or its equivalent) as a practical expedient. These investments have not been classified in the fair value hierarchy. The fair value amounts presented in the above table are intended to permit reconciliation of the fair value hierarchy to the amounts presented on the condensed consolidated statement of financial position. Trading investments classified as level 2 in the above table were comprised of U.S. Treasury Bills carried at amortized cost, which approximates fair value. Trading investments in preferred securities classified as level 2 were comprised of corporate debt and certain preferred securities. The fair value amounts were generally determined using third-party pricing services. The pricing services may utilize evaluated pricing models that vary by asset class and incorporate available trade, bid and other market information. Since these securities do not trade on a daily basis, the pricing services evaluate pricing applications and apply available information through processes such as yield curves, benchmarking of like securities, sector groupings, and matrix pricing, to prepare evaluations. Trading investments classified as level 3 in the above table were comprised of limited partnership interests in limited partnership vehicles that invest in private equity vehicles that invest directly in real estate which was valued using a contractual selling price. Trading investments classified as investments measured at NAV (or its equivalent) as a practical expedient in the above table were comprised of limited partnership interests in limited partnership vehicles that invest in non-registered real estate funds, which are valued based on the NAVs of the underlying funds. At December 31, 2017 , the Company did not have the ability to redeem these interests. Equity method investments classified as investments measured at NAV (or its equivalent) as a practical expedient in the above table were comprised of partnership interests in Company-sponsored limited partnerships. One such partnership invests in private equity vehicles that invest directly in real estate and non-registered real estate funds and the Company did not have the ability to redeem this investment. The other partnership invests indirectly in exchange-traded commodity futures contracts and other commodity-related derivatives and the Company had the ability to redeem this investment monthly at NAV with prior written notice of 5 days. Available-for-sale investments classified as level 2 in the above table were primarily comprised of corporate bonds and certain preferred securities whose fair values are generally determined using third-party pricing services. The pricing services may utilize pricing models, and inputs into those models may include reported trades, executable bid and ask prices, broker-dealer quotations, prices or yields of similar securities, benchmark curves and other market information. The pricing services may use a matrix approach, which considers information regarding securities with similar characteristics to determine the valuation for a security. Available-for-sale investments classified as investments measured at NAV (or its equivalent) as a practical expedient in the above table were comprised of the Company's co-investment in a Cayman trust invested in global listed infrastructure securities. The following table summarizes the changes in level 3 investments measured at fair value on a recurring basis for the periods presented (in thousands): Three Months Ended 2018 2017 Trading Investments Limited Partnership Interests Balance at beginning of the period $ 605 $ 1,196 Purchases / contributions — 24 Sales / distributions (598 ) — Realized gains (losses) (68 ) — Unrealized gains (losses) 61 256 (1) Transfers into (out of) level 3 — — Balance at end of the period $ — $ 1,476 _________________________ (1) Pertains to unrealized gains (losses) from investments still held at March 31, 2017. Realized and unrealized gains (losses) in the above table were recorded as gain (loss) from investments—net in the Company's condensed consolidated statements of operations. Valuation Techniques In certain instances, debt, equity and preferred securities are valued on the basis of prices from an orderly transaction between market participants provided by reputable broker-dealers or independent pricing services. In determining the value of a particular investment, independent pricing services may use information with respect to transactions in such investments, broker quotes, pricing matrices, market transactions in comparable investments and various relationships between investments. As part of its independent price verification process, the Company generally performs reviews of valuations provided by broker-dealers or independent pricing services. Investments in Company-sponsored funds are valued at their closing price or NAV (or its equivalent) as a practical expedient. Foreign exchange contracts are valued by interpolating a value using the spot foreign exchange rate and forward points (based on the spot rate and currency rate differentials), which are all inputs that are observable in active markets (level 2). In the absence of observable market prices, the Company values its investments using valuation methodologies applied on a consistent basis. For some investments, little market activity may exist; management's determination of fair value is then based on the best information available in the circumstances, and may incorporate management's own assumptions and involves a significant degree of judgment, taking into consideration a combination of internal and external factors. Such investments are valued on a quarterly basis, taking into consideration any changes in key inputs and changes in economic and other relevant conditions, and valuation models are updated accordingly. The valuation process also includes a review by the Company's valuation committee which is comprised of senior members from various departments within the Company, including investment management. The valuation committee provides independent oversight of the valuation policies and procedures. At December 31, 2017, the valuation technique used in the fair value measurement of the Company's level 3 investment, limited partnership interests - direct investment in real estate, of approximately $605,000 was based on a contractual selling price.

Derivatives

Derivatives	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	Derivatives The following tables summarize the notional and fair value of the derivative financial instruments. The notional amount represents the absolute value amount of all outstanding derivative contracts for the periods presented (in thousands): March 31, 2018 Assets Liabilities Notional Fair Value Notional Fair Value Commodity contracts $ 27,227 $ 920 $ 12,170 $ 782 Foreign exchange contracts — — 21,051 910 Total derivatives $ 27,227 $ 920 $ 33,221 $ 1,692 December 31, 2017 Assets Liabilities Notional Fair Value Notional Fair Value Commodity contracts $ 8,939 $ 487 $ 6,876 $ 286 Foreign exchange contracts — — 12,279 64 Total derivatives $ 8,939 $ 487 $ 19,155 $ 350 Investments on the condensed consolidated statements of financial condition of approximately $529,000 and $414,000 at March 31, 2018 and December 31, 2017 , respectively, were held as collateral for futures contracts. The following table summarizes gains (losses) from derivative financial instruments for the periods presented (in thousands): Three Months Ended 2018 2017 Commodity contracts $ (34 ) $ (447 ) Foreign exchange contracts (846 ) (855 ) Total $ (880 ) $ (1,302 )

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic earnings per share is calculated by dividing net income attributable to common stockholders by the weighted average shares outstanding. Diluted earnings per share is calculated using the treasury stock method by dividing net income attributable to common stockholders by the total weighted average shares of common stock outstanding and common stock equivalents. Common stock equivalents are comprised of dilutive potential shares from restricted stock unit awards and are excluded from the computation if their effect is anti-dilutive. Anti-dilutive common stock equivalents of approximately 4,600 and 17,000 shares were excluded from the computation for the three months ended March 31, 2018 and 2017, respectively. The following table reconciles income and share data used in the basic and diluted earnings per share computations for the periods presented (in thousands, except per share data): Three Months Ended 2018 2017 Net income $ 28,924 $ 22,944 Less: Net (income) loss attributable to redeemable noncontrolling interest (1,338 ) 41 Net income attributable to common stockholders $ 27,586 $ 22,985 Basic weighted average shares outstanding 46,683 46,243 Dilutive potential shares from restricted stock units 469 360 Diluted weighted average shares outstanding 47,152 46,603 Basic earnings per share attributable to common stockholders $ 0.59 $ 0.50 Diluted earnings per share attributable to common stockholders $ 0.59 $ 0.49

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The provision for income taxes includes U.S. federal, state, local and foreign taxes. The effective tax rate for the three months ended March 31, 2018 was approximately 22.7% , compared with 35.8% for the three months ended March 31, 2017 . The effective tax rate for the three months ended March 31, 2018 differed from the U.S. federal statutory rate of 21% primarily due to state and foreign taxes, net of a tax benefit related to the delivery of restricted stock units. The effective tax rate for the three months ended March 31, 2017 differed from the U.S. federal statutory rate of 35% primarily due to state and foreign taxes, partially offset by the release of certain tax reserves during the quarter. Deferred income taxes represent the tax effects of the temporary differences between book and tax bases and are measured using enacted tax rates that will be in effect when such items are expected to reverse. The Company's net deferred tax asset was primarily comprised of future income tax deductions attributable to the delivery of unvested restricted stock units. The Company records a valuation allowance, when necessary, to reduce deferred tax assets to an amount that more likely than not will be realized.

Regulatory Requirements

Regulatory Requirements	3 Months Ended
	Mar. 31, 2018
Regulatory Capital Requirements [Abstract]
Regulatory Requirements	Regulatory Requirements CSS, a registered broker-dealer in the U.S., is subject to the SEC's Uniform Net Capital Rule 15c3-1 (the Rule), which requires that broker-dealers maintain a minimum level of net capital, as prescribed by the Rule. At March 31, 2018 , CSS had net capital of approximately $3,480,000 , which exceeded its requirements by approximately $3,279,000 . The Rule also provides that equity capital may not be withdrawn or cash dividends paid if the resulting net capital of a broker-dealer is less than the amount required under the Rule and requires prior notice to the SEC for certain withdrawals of capital. CSS does not carry customer accounts and is exempt from SEC Rule 15c3-3 pursuant to provisions (k)(1) and (k)(2)(i) of such rule. CSAL and CSUK are regulated outside the U.S. by the Hong Kong Securities and Futures Commission and the United Kingdom Financial Conduct Authority, respectively. At March 31, 2018 , CSAL and CSUK had aggregate regulatory capital of approximately $79,803,000 , which exceeded aggregate regulatory capital requirements by approximately $75,055,000 .

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions The Company is an investment adviser to, and has administrative agreements with, affiliated funds for which certain employees are officers and/or directors. The following table summarizes the amount of revenue the Company earned from these affiliated funds for the periods presented (in thousands): Three Months Ended 2018 2017 Investment advisory and administration fees (1) $ 59,304 $ 55,528 Distribution and service fees 7,400 7,396 Total $ 66,704 $ 62,924 _________________________ (1) Investment advisory and administration fees are reflected net of fund reimbursements of $2.7 million and $2.4 million for the three months ended March 2018 and 2017, respectively. The following table summarizes sales proceeds, gross realized gains, gross realized losses and dividend income from investments in Company-sponsored funds for the periods presented (in thousands): Three Months Ended 2018 2017 Proceeds from sales $ — $ 5,035 Gross realized gains — 20 Gross realized losses — — Dividend income 152 255 Included in accounts receivable at March 31, 2018 and December 31, 2017 are receivables due from Company-sponsored funds of approximately $22,607,000 and $23,666,000 , respectively.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Rent expense charged to operations, including escalation charges for real estate taxes and other expenses, was approximately $2,966,000 and $2,800,000 and for the three months ended March 31, 2018 and 2017, respectively. From time to time, the Company is involved in legal matters relating to claims arising in the ordinary course of business. At March 31, 2018 , there are no matters pending that the Company believes could have a material adverse effect on its condensed consolidated statement of financial position, results of operations or cash flows. The Company periodically commits to fund a portion of the equity in certain of its sponsored investment products. The Company has committed to co-invest up to $5.1 million alongside Cohen & Steers Global Realty Partners III-TE, L.P. (GRP-TE), a portion of which is made through GRP-TE and the remainder of which is made through Cohen & Steers Co-Investment Partnership, L.P. for up to 12 years through the life of GRP-TE. At March 31, 2018 , the Company has funded approximately $3.8 million with respect to this commitment. The actual timing for funding the unfunded portion of this commitment is currently unknown, as the drawdown of the Company's unfunded commitment is contingent on the timing of drawdowns by the underlying funds in which GRP-TE invests. At March 31, 2018 , the unfunded commitment was not recorded on the Company's condensed consolidated statements of financial condition.

Concentration of Credit Risk

Concentration of Credit Risk	3 Months Ended
	Mar. 31, 2018
Risks and Uncertainties [Abstract]
Concentration of Credit Risk	Concentration of Credit Risk The Company's cash and cash equivalents are principally on deposit with three major financial institutions. The Company is subject to credit risk should these financial institutions be unable to fulfill their obligations.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The Company has evaluated the need for disclosures and/or adjustments resulting from subsequent events through the date the condensed consolidated financial statements were issued. Other than the items described below and elsewhere in the notes to the financial statements, the Company determined that there were no additional subsequent events that require disclosure and/or adjustment. On May 3, 2018, the Company declared a quarterly dividend on its common stock in the amount of $0.33 per share. The dividend will be payable on June 21, 2018 to stockholders of record at the close of business on May 31, 2018.

Basis of Presentation and Sig22

Basis of Presentation and Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements —In May 2017, the FASB issued new guidance for modification accounting related to share-based payment transactions in order to provide clarity and to reduce current diversity in practice. This new guidance does not fundamentally change the notion of a modification. Instead, the amendments clarify which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. The amendments became effective on January 1, 2018 and required prospective application. The Company's adoption of the new guidance did not have a material effect on its condensed consolidated financial statements and related disclosures. In August 2016, the FASB amended the current guidance on the classification of certain cash receipts and payments in the statement of cash flows. This guidance is intended to unify the currently diverse presentations and classifications, including debt prepayment or debt extinguishment costs, settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies, distributions received from equity method investees, beneficial interests in securitization transactions, and separately identifiable cash flows and application of the predominance principle. The Company evaluated the eight issues and concluded that only distributions received from equity method investees is applicable to the Company. This amended guidance became effective on January 1, 2018 and was adopted retrospectively. The Company made an accounting policy election to use the Cumulative Earnings Approach when determining whether distributions received from equity method investments should be classified as either operating or investing activities within its condensed consolidated statements of cash flows. The Company's adoption and application of the new guidance did not have a material effect on its condensed consolidated financial statements and related disclosures. In January 2016, the FASB issued new guidance amending the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. In addition, the FASB clarified guidance related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale debt securities. This new guidance became effective on January 1, 2018 and required the Company to recognize a cumulative-effect adjustment to the beginning retained earnings of approximately $1,095,000 , net of tax. Furthermore, changes in the fair value of the Company’s equity investments carried at fair value are now reported through earnings rather than through other comprehensive income. Additionally, due to the required cumulative-effect method of adoption applied, certain disclosures for prior periods have not been recast to conform with the current period presentation. Lastly, upon adoption of the new guidance, the Company reclassified certain investments previously classified as available-for-sale to trading investments or equity investments at fair value. See Notes 4 and 5 for further discussion about the Company's investments. In May 2014, the FASB issued new guidance which outlined a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. The core principle of the revenue model is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The FASB issued a number of amendments and revisions to the new standard in order to provide more detailed guidance and clarifications. This new guidance became effective on January 1, 2018 and the Company elected to adopt the standard using the retrospective method, which required the recasting of prior period amounts. The adoption of the new standard did not have a material impact on the timing of recognition for the Company's revenue but did affect the presentation of certain revenue and expenses on either a gross or net basis.
Accounting Estimates	Accounting Estimates —The preparation of the condensed consolidated financial statements in conformity with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the dates of the condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting periods. Management believes the estimates used in preparing the condensed consolidated financial statements are reasonable and prudent. Actual results could differ from those estimates.
Consolidation of Company-sponsored Funds	Consolidation of Company-sponsored Funds —Investments in Company-sponsored funds and management fees are evaluated at inception and thereafter, if there is a reconsideration event, in order to determine whether to apply the Variable Interest Entity (VIE) model or the Voting Interest Entity (VOE) model. In performing this analysis, all of the Company's management fees are presumed to be commensurate and at market and are therefore not considered variable interests. A VIE is an entity in which either (i) the equity investment at risk is not sufficient to permit the entity to finance its own activities without additional financial support or (ii) the group of holders of the equity investment at risk lack certain characteristics of a controlling financial interest. The primary beneficiary is the entity that has (i) the power to direct the activities of the VIE that most significantly affect its performance and (i) the obligation to absorb losses of the entity or the right to receive benefits from the entity that could potentially be significant to the VIE. Investments and redemptions or amendments to the governing documents of the respective entities could affect an entity's status as a VIE or the determination of the primary beneficiary. The Company assesses whether it is the primary beneficiary of any VIEs identified by evaluating its economic interests in the entity held either directly by the Company and its affiliates or indirectly through employees. VIEs for which the Company is deemed to be the primary beneficiary are consolidated. Investments in Company-sponsored funds that are determined to be VOEs are consolidated when the Company's ownership interest is greater than 50% of the outstanding voting interests of the fund or when the Company is the general partner of the fund and the limited partners do not have substantive kick-out or participating rights in the fund. The Company records noncontrolling interests in consolidated funds for which the Company's ownership is less than 100 %.
Cash and Cash Equivalents	Cash and Cash Equivalents —Cash and cash equivalents are on deposit with three major financial institutions and consist of short-term, highly-liquid investments, which are readily convertible into cash and have original maturities of three months or less.
Due from/to Brokers	Due from/to Brokers —Company-sponsored funds that are consolidated transact with brokers for certain investment activities. The clearing and custody operations for these investment activities are performed pursuant to contractual agreements. The due from/to brokers balance represents cash and cash equivalents balances at brokers/custodians and/or receivables and payables for unsettled securities transactions.
Investments	Investments —Management of the Company determines the appropriate classification of its investments at the time of purchase and re-evaluates such determination on an ongoing basis and at each statement of financial condition date. At March 31, 2018 , the Company's investments were comprised of equity investments at fair value, trading investments and equity method investments. Realized and unrealized gains and losses on equity investments at fair value, trading investments and equity method investments are recorded in gain (loss) from investments—net in the Company's condensed consolidated statements of operations. Investments classified as equity method investments represent seed investments in which the Company owns between 20 - 50% of the outstanding voting interests in the affiliated fund or when it is determined that the Company is able to exercise significant influence but not control over the investments. When using the equity method, the Company recognizes its respective share of the affiliated investee fund net income or loss for the period which is recorded as gain (loss) from investments—net in the Company's condensed consolidated statements of operations. At March 31, 2018 , the Company's equity method investment consisted of an interest in a Company-sponsored limited partnership which measures its underlying investments at fair value based on quoted market prices or NAV (or its equivalent) as a practical expedient and reports a net asset value on a recurring basis. The carrying amount of this investment approximated its fair value. From time to time, the affiliated funds consolidated by the Company enter into derivative contracts to gain exposure to the underlying commodities markets or to hedge market and credit risks of the underlying portfolios utilizing options and futures contracts. These instruments are measured at fair value based on their settlement price at the close of trading on the associated commodities exchange or board of trade with gains and losses recorded as gain (loss) from investments—net in the Company's condensed consolidated statements of operations. The fair values of these instruments are recorded in other assets or other liabilities and accrued expenses on the Company's condensed consolidated statements of financial condition. At March 31, 2018 , none of the outstanding derivative contracts were subject to a master netting agreement or other similar arrangement. Additionally, from time to time, the Company enters into foreign exchange contracts to hedge its currency exposure related to certain client receivables. These instruments are measured at fair value with gains and losses recorded in other non-operating income (loss) in the Company's condensed consolidated statements of operations. The fair values of these contracts are recorded in other assets or other liabilities and accrued expenses on the Company's condensed consolidated statements of financial condition.
Goodwill and Intangible Assets	Goodwill and Intangible Assets —Goodwill represents the excess of the cost of the Company's investment in the net assets of an acquired company over the fair value of the underlying identifiable net assets at the date of acquisition. Goodwill and indefinite-lived intangible assets are not amortized but are tested at least annually for impairment by comparing the fair value to their carrying amounts. Finite-lived intangible assets are amortized over their useful lives and are tested for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable.
Redeemable Noncontrolling Interest	Redeemable Noncontrolling Interest —Redeemable noncontrolling interest represents third-party interests in the Company's consolidated funds. This interest is redeemable at the option of the investors and therefore is not treated as permanent equity. Redeemable noncontrolling interest is remeasured at redemption value which approximates the fair value at each reporting period.
Stock-based Compensation	Stock-based Compensation —The Company recognizes compensation expense for the grant-date fair value of awards of equity instruments to employees. This expense is recognized over the period during which employees are required to provide service. Forfeitures are recorded as incurred.
Income Taxes	Income Taxes —The Company records the current and deferred tax consequences of all transactions that have been recognized in the condensed consolidated financial statements in accordance with the provisions of the enacted tax laws. Deferred tax assets are recognized for temporary differences that will result in deductible amounts in future years at tax rates that are expected to apply in those years. Deferred tax liabilities are recognized for temporary differences that will result in taxable income in future years at tax rates that are expected to apply in those years. The Company records a valuation allowance, when necessary, to reduce deferred tax assets to an amount that more likely than not will be realized. The effective tax rate for interim periods represents the Company's best estimate of the effective tax rate expected to be applied to the full fiscal year. The calculation of tax liabilities involves dealing with uncertainties in the application of complex tax laws and regulations in a multitude of jurisdictions across the Company's global operations. A tax benefit from an uncertain tax position may be recognized when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, on the basis of the technical merits. The Company records potential interest and penalties related to uncertain tax positions in the provision for income taxes in the condensed consolidated statements of operations.
Currency Translation and Transactions	Currency Translation and Transactions —Assets and liabilities of subsidiaries having non-U.S. dollar functional currencies are translated at exchange rates at the applicable condensed consolidated statement of financial condition date. Revenue and expenses of such subsidiaries are translated at average exchange rates during the period. The gains or losses resulting from translating non-U.S. dollar functional currency into U.S. dollars are included in the Company's condensed consolidated statements of comprehensive income. The cumulative translation adjustment was $(4,228,000) and $(4,781,000) at March 31, 2018 and December 31, 2017 , respectively. Gains or losses resulting from non-U.S. dollar currency transactions are included in other non-operating income (loss) in the condensed consolidated statements of operations.
Comprehensive Income	Comprehensive Income —The Company reports all changes in comprehensive income in the condensed consolidated statements of comprehensive income. Comprehensive income includes net income or loss attributable to common stockholders and amounts attributable to foreign currency translation gain (loss), net of tax.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements —In February 2018, the FASB issued new guidance allowing entities to reclassify certain tax effects related to the enactment of the Tax Cuts and Jobs Act (the Tax Act) from accumulated other comprehensive income (AOCI) to retained earnings. Prior to the issuance of the new guidance, a portion of the previously recognized deferred tax effects recorded in AOCI was "left stranded" in AOCI as the effect of remeasuring the deferred taxes using the reduced federal corporate income tax rate was required to be recorded through income. The new guidance allows these stranded tax effects to be reclassified from AOCI to retained earnings. The new guidance will be effective on January 1, 2019, with early adoption permitted and is to be applied either in the period of adoption or retrospectively to each period in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Act is recognized. The Company is still assessing which adoption method it will choose but it does not expect either method to have a material effect on its condensed consolidated financial statements and related disclosures. In August 2017, the FASB issued new guidance amending the accounting for hedging activities. The new guidance (i) expands hedge accounting for nonfinancial and financial risk components and amends measurement methodologies to more closely align hedge accounting with an entity's risk management activities, (ii) decreases the complexity of preparing and understanding hedge results through eliminating the separate measurement and reporting of hedge ineffectiveness, (iii) enhances transparency, comparability and understandability of hedge results through enhanced disclosures and changing the presentation of hedge results to align the effects of the hedging instrument and the hedged item and (iv) reduces the cost and complexity of applying hedge accounting by simplifying the manner in which assessments of hedge effectiveness may be performed. The new guidance will be effective on January 1, 2019, with early adoption permitted. The Company does not expect the adoption of the new guidance to have a material effect on its condensed consolidated financial statements and related disclosures. In January 2017, the FASB issued guidance to simplify the goodwill impairment test by removing the requirement to perform a hypothetical purchase price allocation. A goodwill impairment will now be the amount by which a reporting unit's carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. This new guidance will be effective on January 1, 2020. The Company does not expect the adoption of the new guidance to have a material effect on its condensed consolidated financial statements and related disclosures. In February 2016, the FASB issued guidance introducing a new lease model which requires lessees to recognize leases on-balance sheet and disclose key information about leasing arrangements. The new guidance establishes a right-of-use model (ROU) that requires a lessee to recognize an ROU asset and lease liability on the balance sheet for all leases with a term longer than 12 months. Leases will be classified as finance or operating, with classification affecting the pattern and classification of expense recognition in the income statement. The new guidance also requires disclosures by lessees and lessors to enable users of financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. The new guidance is effective on January 1, 2019, with early adoption permitted. The Company expects to adopt the new guidance on its effective date. A modified retrospective transition approach is required for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. While the Company is continuing to assess the effect of adoption, it currently believes the most significant change relates to the recognition of new ROU assets and lease liabilities on its condensed consolidated statements of financial condition for its office space and other operating leases. The Company does not expect a significant change in its leasing activity between now and adoption. The Company is still assessing which of the available practical expedients it plans to elect upon adoption.
Valuation Techniques	Valuation Techniques In certain instances, debt, equity and preferred securities are valued on the basis of prices from an orderly transaction between market participants provided by reputable broker-dealers or independent pricing services. In determining the value of a particular investment, independent pricing services may use information with respect to transactions in such investments, broker quotes, pricing matrices, market transactions in comparable investments and various relationships between investments. As part of its independent price verification process, the Company generally performs reviews of valuations provided by broker-dealers or independent pricing services. Investments in Company-sponsored funds are valued at their closing price or NAV (or its equivalent) as a practical expedient. Foreign exchange contracts are valued by interpolating a value using the spot foreign exchange rate and forward points (based on the spot rate and currency rate differentials), which are all inputs that are observable in active markets (level 2). In the absence of observable market prices, the Company values its investments using valuation methodologies applied on a consistent basis. For some investments, little market activity may exist; management's determination of fair value is then based on the best information available in the circumstances, and may incorporate management's own assumptions and involves a significant degree of judgment, taking into consideration a combination of internal and external factors. Such investments are valued on a quarterly basis, taking into consideration any changes in key inputs and changes in economic and other relevant conditions, and valuation models are updated accordingly. The valuation process also includes a review by the Company's valuation committee which is comprised of senior members from various departments within the Company, including investment management. The valuation committee provides independent oversight of the valuation policies and procedures.

Basis of Presentation and Sig23

Basis of Presentation and Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	The adoption of the new revenue recognition standard resulted in the following changes to the Company's previously reported results for the three months ended March 31, 2017 (in thousands): As Previously Reported Net Adjustments Due to New Revenue Standard As Recasted Revenue: Investment advisory and administration fees $ 81,903 $ (2,295 ) $ 79,608 Distribution and service fees 5,046 2,350 7,396 Total $ 86,949 $ 55 $ 87,004 Expenses: Distribution and service fees $ 9,780 $ 2,429 $ 12,209 General and administrative 12,930 (2,374 ) 10,556 Total $ 22,710 $ 55 $ 22,765

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following tables summarize revenue recognized from contracts with customers by client domicile and revenue by vehicle for all periods presented (in thousands): Three Months Ended 2018 2017 Client domicile: North America $ 79,707 $ 73,380 Japan 9,093 11,125 Asia excluding Japan 3,035 2,647 Europe 2,629 2,589 Total $ 94,464 $ 89,741 Three Months Ended 2018 2017 Vehicle: Open-end funds (1) $ 47,452 $ 43,954 Closed-end funds 19,177 18,880 Institutional accounts 25,205 24,170 Portfolio consulting and other 2,630 2,737 Total $ 94,464 $ 89,741 ________________________ (1) Included distribution and service fees of $7.4 million for both the three months ended March 31, 2018 and 2017.

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2018
Investments [Abstract]
Summary Investment Holdings	The following tables summarize the Company's investments for the periods presented (in thousands): March 31, 2018 Equity investments at fair value $ 43,615 Trading investments 95,785 Equity method investments 35 Total investments $ 139,435 December 31, 2017 Trading investments $ 74,856 Equity method investments 6,176 Available-for-sale investments 27,074 Total investments $ 108,106
Gain (Loss) on Investments	ain (loss) from investments for the for the periods presented (in thousands): Three Months Ended March 31, 2018 Gain (loss) from investments—net (1) Net realized gains (losses) during the period $ 155 Net unrealized gains (losses) during the period on investments still held at the end of the period (4,657 ) Gain (loss) from investments—net $ (4,502 ) ________________________ (1) Includes net income (loss) attributable to redeemable noncontrolling interest. Three Months Ended March 31, 2017 Gain (loss) from trading investments—net (1) $ 273 Equity in earnings (losses) of affiliates—net (289 ) Gain (loss) from available-for-sale investments—net 35 Total gain (loss) from investments $ 19 _________________________ (1) Includes net income (loss) attributable to redeemable noncontrolling interest.
Schedule of Variable Interest Entities	The following tables summarize the condensed consolidated statements of financial condition attributable to the Company's consolidated VIEs, which included the Cohen & Steers SICAV Global Listed Infrastructure Fund (GLI SICAV), the Cohen & Steers Co-Investment Partnership, L.P. (GRP-CIP) and the Cohen & Steers SICAV Global Preferred Securities Fund (SICAV Preferred) for the periods presented (in thousands): March 31, 2018 GLI SICAV GRP-CIP SICAV Preferred Total Assets (1) Investments $ 5,648 $ 723 $ 93,440 $ 99,811 Due from brokers 190 191 9,212 9,593 Other assets 186 — 1,587 1,773 Total assets $ 6,024 $ 914 $ 104,239 $ 111,177 Liabilities (1) Due to brokers $ 50 $ — $ 7,057 $ 7,107 Other liabilities and accrued expenses 99 5 234 338 Total liabilities $ 149 $ 5 $ 7,291 $ 7,445
Schedule of Available-for-sale Investments Reconciliation	The following table summarizes the cost, gross unrealized gains, gross unrealized losses and fair value of available-for-sale investments at December 31, 2017 (in thousands): December 31, 2017 Cost Gross Unrealized Gains Gross (1) Fair Value Common stocks $ 6,782 $ 639 $ (183 ) $ 7,238 Company-sponsored funds 13,376 1,269 (13 ) 14,632 Fixed income 3,966 15 (20 ) 3,961 Preferred securities 1,100 29 (5 ) 1,124 Other 100 19 — 119 Total available-for-sale investments $ 25,324 $ 1,971 $ (221 ) $ 27,074 _________________________ (1) At December 31, 2017 , there were no investments with material unrealized losses continuously for a period of more than 12 months.
Realized Gain (Loss) on Investments	The following table summarizes sales proceeds, gross realized gains and losses from available-for-sale investments for the three months ended March 31, 2017 (in thousands): Three Months Ended March 31, 2017 Proceeds from sales $ 6,886 Gross realized gains 98 Gross realized losses (63 )

Fair Value (Tables)

Fair Value (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements, Recurring and Nonrecurring	The following table presents fair value measurements at December 31, 2017 (in thousands): Level 1 Level 2 Level 3 Investments Measured at NAV Total Cash equivalents $ 173,270 $ — $ — $ — $ 173,270 Trading investments Common stocks $ 5,961 $ — $ — $ — $ 5,961 Fixed income — 6,755 — — 6,755 Limited partnership interests — — 605 725 1,330 Preferred securities 7,658 53,152 — — 60,810 Total $ 13,619 $ 59,907 $ 605 $ 725 $ 74,856 Equity method investments $ — $ — $ — $ 6,176 $ 6,176 Available-for-sale investments Common stocks $ 7,238 $ — $ — $ — $ 7,238 Company-sponsored funds 14,632 — — — 14,632 Fixed income — 3,961 — — 3,961 Preferred securities 999 125 — — 1,124 Other — — — 119 119 Total $ 22,869 $ 4,086 $ — $ 119 $ 27,074 Total investments $ 36,488 $ 63,993 $ 605 $ 7,020 $ 108,106 Derivatives - assets Commodity contracts 487 — — — 487 Foreign exchange contracts — — — — — Total $ 487 $ — $ — $ — $ 487 Derivatives - liabilities Commodity contracts $ 286 $ — $ — $ — $ 286 Foreign exchange contracts — 64 — — 64 Total $ 286 $ 64 $ — $ — $ 350 The following table presents fair value measurements at March 31, 2018 (in thousands): Level 1 Level 2 Level 3 Investments Measured at NAV Total Cash equivalents $ 159,008 $ — $ — $ — $ 159,008 Equity investments at fair value Common stocks $ 13,668 $ — $ — $ — $ 13,668 Company-sponsored funds 14,063 — — — 14,063 Limited partnership interests 623 — — 723 1,346 Preferred securities 13,883 546 — — 14,429 Other — — — 109 109 Total $ 42,237 $ 546 $ — $ 832 $ 43,615 Trading investments Fixed income $ 3,966 $ 91,819 $ — $ — $ 95,785 Total $ 3,966 $ 91,819 $ — $ — $ 95,785 Equity method investments $ — $ — $ — $ 35 $ 35 Total investments $ 46,203 $ 92,365 $ — $ 867 $ 139,435 Derivatives - assets Commodity contracts $ 920 $ — $ — $ — $ 920 Foreign exchange contracts — — — — — Total $ 920 $ — $ — $ — $ 920 Derivatives - liabilities Commodity contracts $ 782 $ — $ — $ — $ 782 Foreign exchange contracts — 910 — — 910 Total $ 782 $ 910 $ — $ — $ 1,692
Fair Value, Valuation Technique, Unobservable Inputs	The following table summarizes the changes in level 3 investments measured at fair value on a recurring basis for the periods presented (in thousands): Three Months Ended 2018 2017 Trading Investments Limited Partnership Interests Balance at beginning of the period $ 605 $ 1,196 Purchases / contributions — 24 Sales / distributions (598 ) — Realized gains (losses) (68 ) — Unrealized gains (losses) 61 256 (1) Transfers into (out of) level 3 — — Balance at end of the period $ — $ 1,476 _________________________ (1) Pertains to unrealized gains (losses) from investments still held at March 31, 2017.

Derivatives (Tables)

Derivatives (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	December 31, 2017 Assets Liabilities Notional Fair Value Notional Fair Value Commodity contracts $ 8,939 $ 487 $ 6,876 $ 286 Foreign exchange contracts — — 12,279 64 Total derivatives $ 8,939 $ 487 $ 19,155 $ 350 The following tables summarize the notional and fair value of the derivative financial instruments. The notional amount represents the absolute value amount of all outstanding derivative contracts for the periods presented (in thousands): March 31, 2018 Assets Liabilities Notional Fair Value Notional Fair Value Commodity contracts $ 27,227 $ 920 $ 12,170 $ 782 Foreign exchange contracts — — 21,051 910 Total derivatives $ 27,227 $ 920 $ 33,221 $ 1,692
Gains (losses) on Derivatives	ains (losses) from derivative financial instruments for the periods presented (in thousands): Three Months Ended 2018 2017 Commodity contracts $ (34 ) $ (447 ) Foreign exchange contracts (846 ) (855 ) Total $ (880 ) $ (1,302 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table reconciles income and share data used in the basic and diluted earnings per share computations for the periods presented (in thousands, except per share data): Three Months Ended 2018 2017 Net income $ 28,924 $ 22,944 Less: Net (income) loss attributable to redeemable noncontrolling interest (1,338 ) 41 Net income attributable to common stockholders $ 27,586 $ 22,985 Basic weighted average shares outstanding 46,683 46,243 Dilutive potential shares from restricted stock units 469 360 Diluted weighted average shares outstanding 47,152 46,603 Basic earnings per share attributable to common stockholders $ 0.59 $ 0.50 Diluted earnings per share attributable to common stockholders $ 0.59 $ 0.49

Related Party Transactions (Tab

Related Party Transactions (Tables)	3 Months Ended
	Mar. 31, 2018
Related Party Transactions [Abstract]
Schedule of Related Party Transactions	The following table summarizes the amount of revenue the Company earned from these affiliated funds for the periods presented (in thousands): Three Months Ended 2018 2017 Investment advisory and administration fees (1) $ 59,304 $ 55,528 Distribution and service fees 7,400 7,396 Total $ 66,704 $ 62,924 _________________________ (1) Investment advisory and administration fees are reflected net of fund reimbursements of $2.7 million and $2.4 million for the three months ended March 2018 and 2017, respectively. The following table summarizes sales proceeds, gross realized gains, gross realized losses and dividend income from investments in Company-sponsored funds for the periods presented (in thousands): Three Months Ended 2018 2017 Proceeds from sales $ — $ 5,035 Gross realized gains — 20 Gross realized losses — — Dividend income 152 255

Basis of Presentation and Sig30

Basis of Presentation and Significant Accounting Policies Less than wholly owned subsidiaries (Details)	3 Months Ended
	Mar. 31, 2018
Minimum
VIE ownership percentage	50.00%
Maximum
Minority interest	100.00%

Basis of Presentation and Sig31

Basis of Presentation and Significant Accounting Policies Cash Equivalents Original Maturities (Details)	Mar. 31, 2016
Maximum
Restricted Cash and Cash Equivalents Items [Line Items]
Contractual Maturities of Time Deposits, $100,000 or More, Description	3 months

Basis of Presentation and Sig32

Basis of Presentation and Significant Accounting Policies Current Translation and Transactions (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accumulated Translation Adjustment
Cumulative Translation Adjustments balance [Line Items]
Cumulative foreign currency translation	$ (4,228)	$ (4,781)

Basis of Presentation and Sig33

Basis of Presentation and Significant Accounting Policies New Accounting Pronouncements (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment advisory and administration fees	$ 84,434,000	$ 79,608,000
Distribution and service fees	7,400,000	7,396,000
Total revenue	94,464,000	89,741,000
Distribution and service fees	12,842,000	13,163,000
General and administrative	12,185,000	10,556,000
Total expenses	57,245,000	54,213,000
Cumulative effect of new accounting principle	$ (125,293,000)			$ (137,972,000)
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment advisory and administration fees		79,608,000
Distribution and service fees		7,396,000
Total revenue		87,004,000
Distribution and service fees		12,209,000
General and administrative		10,556,000
Total expenses		22,765,000
As Previously Reported | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment advisory and administration fees		81,903,000
Distribution and service fees		5,046,000
Total revenue		86,949,000
Distribution and service fees		9,780,000
General and administrative		12,930,000
Total expenses		22,710,000
Net Adjustments Due to New Revenue Standard | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment advisory and administration fees		(2,295,000)
Distribution and service fees		2,350,000
Total revenue		55,000
Distribution and service fees		2,429,000
General and administrative		(2,374,000)
Total expenses		$ 55,000
Cumulative effect of new accounting principle			$ 1,095,000

Basis of Presentation and Sig34

Basis of Presentation and Significant Accounting Policies Consolidation (Details)	Mar. 31, 2018	Dec. 31, 2017
Minimum
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		2000.00%
Maximum
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	50.00%

Revenue (Details)

Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 94,464	$ 89,741
Investment advisory and administration fees	84,434	79,608
Distribution and service fees	7,400	7,396
Institutional:
Disaggregation of Revenue [Line Items]
Revenues	25,205	24,170
Portfolio consulting and other
Disaggregation of Revenue [Line Items]
Revenues	2,630	2,737
Open-end funds | Vehicle:
Disaggregation of Revenue [Line Items]
Revenues	47,452	43,954
Investment advisory and administration fees	40,100	36,600
Distribution and service fees	7,400	0
Closed-end funds | Vehicle:
Disaggregation of Revenue [Line Items]
Revenues	19,177	18,880
North America
Disaggregation of Revenue [Line Items]
Revenues	79,707	73,380
Japan
Disaggregation of Revenue [Line Items]
Revenues	9,093	11,125
Asia, Excluding Japan
Disaggregation of Revenue [Line Items]
Revenues	3,035	2,647
Europe
Disaggregation of Revenue [Line Items]
Revenues	$ 2,629	$ 2,589

Investments Trading and Equity

Investments Trading and Equity Investments (Details) $ in Thousands		3 Months Ended
		Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)new_funds_seeded	Mar. 31, 2017USD ($)
Trading Securities and Other Trading Assets [Line Items]
Number of new funds seeded | new_funds_seeded			1
Investments		$ 43,615	$ 74,856
Equity method investments		95,785	6,176
Available-for-sale investments		35	27,074
Investments	[1],[2]	139,435	$ 108,106
Gain (Loss) on Investments [Abstract]
Net realized gains (losses) during the period		155
Net unrealized gains (losses) during the period on investments still held at the end of the period		(4,657)
Gain (loss) from trading investments—net				$ 273
Equity in earnings (losses) of affiliates—net				(289)
Gain (loss) from available-for-sale investments—net				35
Total gain (loss) from seed investments		$ (4,502)		$ 19
[1]	Asset and liability amounts in parentheses represent the aggregated balances at March 31, 2018 and December 31, 2017 attributable to the Cohen & Steers SICAV Global Listed Infrastructure Fund, the Cohen & Steers Co-Investment Partnership, L.P. and the Cohen & Steers SICAV Global Preferred Securities Fund, respectively.
[2]	Pledged as collateral attributable to the consolidated balances of the Cohen & Steers Active Commodities Strategy Fund, Inc. at March 31, 2018 and December 31, 2017, respectively.

Investments Variable Interest E

Investments Variable Interest Entity (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Trading investments		$ 43,615	$ 74,856
Due from broker	[1]	11,790	6,429
Other Assets	[1]	8,698	7,053
Assets		428,941	410,125
Due to broker	[1]	7,137	3,282
Other liabilities and accrued expenses	[1]	10,492	10,025
Liabilities		63,494	86,794
GLI SICAV
Variable Interest Entity [Line Items]
Trading investments		5,648	5,961
Due from broker		190	285
Other Assets		186	32
Assets		6,024	6,278
Due to broker		50	35
Other liabilities and accrued expenses		99	87
Liabilities		149	122
GRP-CIP
Variable Interest Entity [Line Items]
Trading investments		723	1,330
Due from broker		191	202
Other Assets		0	0
Assets		914	1,532
Due to broker		0	0
Other liabilities and accrued expenses		5	5
Liabilities		5	5
SICAV Preferred
Variable Interest Entity [Line Items]
Trading investments		93,440	60,810
Due from broker		9,212	4,923
Other Assets		1,587	899
Assets		104,239	66,632
Due to broker		7,057	3,168
Other liabilities and accrued expenses		234	199
Liabilities		7,291	3,367
GLI SICAV, GRP-CIP and SICAV Preferred
Variable Interest Entity [Line Items]
Trading investments		99,811	68,101
Due from broker		9,593	5,410
Other Assets		1,773	931
Assets		111,177	74,442
Due to broker		7,107	3,203
Other liabilities and accrued expenses		338	291
Liabilities		$ 7,445	$ 3,494
[1]	Asset and liability amounts in parentheses represent the aggregated balances at March 31, 2018 and December 31, 2017 attributable to the Cohen & Steers SICAV Global Listed Infrastructure Fund, the Cohen & Steers Co-Investment Partnership, L.P. and the Cohen & Steers SICAV Global Preferred Securities Fund, respectively.

Investments Available-for-Sale

Investments Available-for-Sale Invsetments (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2018	Dec. 31, 2017
Available-for-sale Investments [Abstract]
Cost				$ 25,324
Gross Unrealized Gains				1,971
Gross Unrealized Losses	[1]			(221)
Fair Value			$ 35	27,074
Available-for-sale investments in an unrealized loss position				6,086
Proceeds from Investing Activities [Abstract]
Proceeds from sales		$ 6,886
Gross realized gains		98
Gross realized losses		$ (63)
Common stocks
Available-for-sale Investments [Abstract]
Cost				6,782
Gross Unrealized Gains				639
Gross Unrealized Losses	[1]			(183)
Fair Value				7,238
Company-sponsored funds
Available-for-sale Investments [Abstract]
Cost				13,376
Gross Unrealized Gains				1,269
Gross Unrealized Losses	[1]			(13)
Fair Value				14,632
Fixed income securities
Available-for-sale Investments [Abstract]
Cost				3,966
Gross Unrealized Gains				15
Gross Unrealized Losses				(20)
Fair Value				3,961
Preferred securities
Available-for-sale Investments [Abstract]
Cost				1,100
Gross Unrealized Gains				29
Gross Unrealized Losses	[1]			(5)
Fair Value				1,124
Other
Available-for-sale Investments [Abstract]
Cost				100
Gross Unrealized Gains				19
Gross Unrealized Losses				0
Fair Value				$ 119
[1]	At December 31, 2017, there were no investments with material unrealized losses continuously for a period of more than 12 months.

Fair Value (Details)

Fair Value (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period		5 days
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		$ 43,615		$ 74,856
Equity method investments		95,785		6,176
Available-for-sale investments		35		27,074
Investments	[1],[2]	139,435		108,106
Investments Measured at NAV		832
Fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV				0
Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0
Common Stocks
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0
Company-sponsored funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV				0
Limited partnership interests
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		723		725
Preferred securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0
Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		109		119
Trading Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		725
Equity Method Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		35		6,176
Available-for-sale Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		867
Derivatives - Assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0
Derivatives - Liabilities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		$ 0		$ 0
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Method Investment, Ownership Percentage				2000.00%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Method Investment, Ownership Percentage		50.00%
Foreign exchange contracts | Derivatives - Assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		$ 0		$ 0
Foreign exchange contracts | Derivatives - Liabilities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0
Commodity contracts | Derivatives - Assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0
Commodity contracts | Derivatives - Liabilities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		$ 0		0
Cohen & Steers Global Realty Partners III-TE, L.P. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Method Investment, Ownership Percentage		0.20%
Common Stocks
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments				7,238
Company-sponsored funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments				14,632
Investments Measured at NAV		$ 0
Preferred securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments				1,124
Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments				119
Fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments				3,961
Fixed income securities | Trading Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Cash equivalents				173,270
Trading investments		43,615		74,856
Equity method investments				6,176
Available-for-sale investments				27,074
Investments Measured at NAV				119
Derivative - assets		920		487
Derivative - liabilities		1,692		350
Fair Value, Measurements, Recurring | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Cash equivalents		159,008
Fair Value, Measurements, Recurring | Trading Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Equity method investments		95,785
Fair Value, Measurements, Recurring | Equity Method Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Equity method investments		35
Fair Value, Measurements, Recurring | Available-for-sale Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		139,435		108,106
Investments Measured at NAV				7,020
Fair Value, Measurements, Recurring | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		0
Derivative - liabilities		910
Fair Value, Measurements, Recurring | Foreign exchange contracts | Derivatives - Liabilities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities				64
Fair Value, Measurements, Recurring | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		920		487
Derivative - liabilities		782		286
Fair Value, Measurements, Recurring | Common Stocks
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		13,668		5,961
Available-for-sale investments				7,238
Fair Value, Measurements, Recurring | Company-sponsored funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		14,063
Available-for-sale investments				14,632
Fair Value, Measurements, Recurring | Limited partnership interests
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		1,346		1,330
Fair Value, Measurements, Recurring | Preferred securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		14,429		60,810
Available-for-sale investments				1,124
Fair Value, Measurements, Recurring | Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments				119
Fair Value, Measurements, Recurring | Other | Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments		109
Fair Value, Measurements, Recurring | Fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments				6,755
Available-for-sale investments				3,961
Fair Value, Measurements, Recurring | Fixed income securities | Trading Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		95,785
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Cash equivalents				173,270
Trading investments		42,237		13,619
Equity method investments				0
Available-for-sale investments				22,869
Derivative - assets		920		487
Derivative - liabilities		782		286
Fair Value, Measurements, Recurring | Level 1 | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Cash equivalents		159,008
Fair Value, Measurements, Recurring | Level 1 | Trading Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Equity method investments		3,966
Fair Value, Measurements, Recurring | Level 1 | Equity Method Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Equity method investments		0
Fair Value, Measurements, Recurring | Level 1 | Available-for-sale Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		46,203		36,488
Fair Value, Measurements, Recurring | Level 1 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		0		0
Derivative - liabilities		0
Fair Value, Measurements, Recurring | Level 1 | Foreign exchange contracts | Derivatives - Liabilities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities				0
Fair Value, Measurements, Recurring | Level 1 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		920		487
Derivative - liabilities		782		286
Fair Value, Measurements, Recurring | Level 1 | Common Stocks
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		13,668		5,961
Available-for-sale investments				7,238
Fair Value, Measurements, Recurring | Level 1 | Company-sponsored funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		14,063
Available-for-sale investments				14,632
Fair Value, Measurements, Recurring | Level 1 | Limited partnership interests
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		623		0
Fair Value, Measurements, Recurring | Level 1 | Preferred securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		13,883		7,658
Available-for-sale investments				999
Fair Value, Measurements, Recurring | Level 1 | Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments				0
Fair Value, Measurements, Recurring | Level 1 | Other | Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments		0
Fair Value, Measurements, Recurring | Level 1 | Fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments				0
Available-for-sale investments				0
Fair Value, Measurements, Recurring | Level 1 | Fixed income securities | Trading Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		3,966
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Cash equivalents				0
Trading investments		546		59,907
Equity method investments				0
Available-for-sale investments				4,086
Derivative - assets		0		0
Derivative - liabilities		910		64
Fair Value, Measurements, Recurring | Level 2 | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Cash equivalents		0
Fair Value, Measurements, Recurring | Level 2 | Trading Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Equity method investments		91,819
Fair Value, Measurements, Recurring | Level 2 | Equity Method Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Equity method investments		0
Fair Value, Measurements, Recurring | Level 2 | Available-for-sale Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		92,365		63,993
Fair Value, Measurements, Recurring | Level 2 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		0		0
Derivative - liabilities		910
Fair Value, Measurements, Recurring | Level 2 | Foreign exchange contracts | Derivatives - Liabilities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities				64
Fair Value, Measurements, Recurring | Level 2 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		0		0
Derivative - liabilities		0		0
Fair Value, Measurements, Recurring | Level 2 | Common Stocks
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		0		0
Available-for-sale investments				0
Fair Value, Measurements, Recurring | Level 2 | Company-sponsored funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		0
Available-for-sale investments				0
Fair Value, Measurements, Recurring | Level 2 | Limited partnership interests
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		0		0
Fair Value, Measurements, Recurring | Level 2 | Preferred securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		546		53,152
Available-for-sale investments				125
Fair Value, Measurements, Recurring | Level 2 | Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments				0
Fair Value, Measurements, Recurring | Level 2 | Other | Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments		0
Fair Value, Measurements, Recurring | Level 2 | Fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments				6,755
Available-for-sale investments				3,961
Fair Value, Measurements, Recurring | Level 2 | Fixed income securities | Trading Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		91,819
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Cash equivalents				0
Trading investments		0		605
Equity method investments				0
Available-for-sale investments				0
Derivative - assets		0		0
Derivative - liabilities		0		0
Fair Value, Measurements, Recurring | Level 3 | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Cash equivalents		0
Fair Value, Measurements, Recurring | Level 3 | Trading Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Equity method investments		0
Fair Value, Measurements, Recurring | Level 3 | Equity Method Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Equity method investments		0
Fair Value, Measurements, Recurring | Level 3 | Available-for-sale Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		0		605
Fair Value, Measurements, Recurring | Level 3 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		0		0
Derivative - liabilities		0
Fair Value, Measurements, Recurring | Level 3 | Foreign exchange contracts | Derivatives - Liabilities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities				0
Fair Value, Measurements, Recurring | Level 3 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		0		0
Derivative - liabilities		0		0
Fair Value, Measurements, Recurring | Level 3 | Common Stocks
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		0		0
Available-for-sale investments				0
Fair Value, Measurements, Recurring | Level 3 | Company-sponsored funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		0
Available-for-sale investments				0
Fair Value, Measurements, Recurring | Level 3 | Limited partnership interests
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		0		605
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		605	$ 1,196
Purchases / contributions		0	24
Sales / distributions		(598)	0
Realized gains (losses)		(68)	0
Unrealized gains (losses)		61	256
Transfers into (out of) level 3		0	0
Balance at end of period		0	$ 1,476
Fair Value, Measurements, Recurring | Level 3 | Preferred securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		0		0
Available-for-sale investments				0
Fair Value, Measurements, Recurring | Level 3 | Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments				0
Fair Value, Measurements, Recurring | Level 3 | Other | Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments		0
Fair Value, Measurements, Recurring | Level 3 | Fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments				0
Available-for-sale investments				$ 0
Fair Value, Measurements, Recurring | Level 3 | Fixed income securities | Trading Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Trading investments		$ 0
[1]	Asset and liability amounts in parentheses represent the aggregated balances at March 31, 2018 and December 31, 2017 attributable to the Cohen & Steers SICAV Global Listed Infrastructure Fund, the Cohen & Steers Co-Investment Partnership, L.P. and the Cohen & Steers SICAV Global Preferred Securities Fund, respectively.
[2]	Pledged as collateral attributable to the consolidated balances of the Cohen & Steers Active Commodities Strategy Fund, Inc. at March 31, 2018 and December 31, 2017, respectively.

Derivatives (Details)

Derivatives (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Derivative [Line Items]
Derivative Assets, Notional	$ 27,227		$ 8,939
Derivative Assets, Fair Value	920		487
Derivative Liabilities, Notional	33,221		19,155
Derivative Liabilities, Fair Value	1,692		350
Trading investments and pledged as collateral	529		414
Derivative, Gains (Losses) on derivative, net	(880)	$ (1,302)
Foreign exchange contracts
Derivative [Line Items]
Derivative Assets, Notional	0		0
Derivative Assets, Fair Value	0		0
Derivative Liabilities, Notional	21,051		12,279
Derivative Liabilities, Fair Value	910		64
Derivative, Gains (Losses) on derivative, net	(846)	(855)
Commodity contracts
Derivative [Line Items]
Derivative Assets, Notional	27,227		8,939
Derivative Assets, Fair Value	920		487
Derivative Liabilities, Notional	12,170		6,876
Derivative Liabilities, Fair Value	782		$ 286
Derivative, Gains (Losses) on derivative, net	$ (34)	$ (447)

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Anti-dilutive common stock equivalents excluded from computation (in shares)	4,600	17,000
Net income	$ 28,924	$ 22,944
Less: Net (income) loss attributable to redeemable noncontrolling interest	(1,338)	41
Net income attributable to common stockholders	$ 27,586	$ 22,985
Basic weighted average shares outstanding (shares)	46,683,000	46,243,000
Dilutive potential shares from restricted stock units (shares)	469,000	360,000
Diluted weighted average shares outstanding (shares)	47,152,000	46,603,000
Basic earnings per share attributable to common stockholders (in dollars per share)	$ 0.59	$ 0.50
Diluted earnings per share attributable to common stockholders (in dollars per share)	$ 0.59	$ 0.49

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Income Tax Contingency [Line Items]
Tax Cuts and Jobs Act of 2017 provisional income tax expense (benefit)	$ 8.4
U.S. Federal, State, Local and Foreign Taxes
Income Tax Contingency [Line Items]
Effective income tax rate reconciliation, percent		22.70%	35.80%

Regulatory Requirements (Detail

Regulatory Requirements (Details) $ in Thousands	Mar. 31, 2018USD ($)
Securities Registered Domestically
Financial Instruments Owned and Pledged as Collateral [Line Items]
Net Capital	$ 3,480
Excess Capital	3,279
Securities Regulated By Foreign Entities
Financial Instruments Owned and Pledged as Collateral [Line Items]
Net Capital	79,803
Excess Capital	$ 75,055

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Related Party Transactions, Revenue [Abstract]
Investment Fund Reimbursements	$ 2,700	$ 2,400
Affiliated Funds
Related Party Transactions, Revenue [Abstract]
Investment advisory and administrative fees	59,304	55,528
Distribution and service fees	7,400	7,396
Total	66,704	62,924
Proceeds from sale, Maturity and Collection of Investment	0	5,035
Gross realized gains	0	20
Gross realized losses	0	0
Dividend income	152	$ 255
Receivables due from company-sponsored mutual funds	$ 22,607		$ 23,666

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Contingencies [Line Items]
Operating Leases, Rent Expense		$ 2,800
Commitments
Contingencies [Line Items]
Long-term purchase commitment, time period	12 years
Commitment to invest
Contingencies [Line Items]
Long-term purchase commitment	$ 5,100
Long-term committment, funded amount	$ 3,800

Concentration of Credit Risk (D

Concentration of Credit Risk (Details)	Mar. 31, 2018financial_institution
Risks and Uncertainties [Abstract]
Number of financial institutions	3

Subsequent Events (Details)

Subsequent Events (Details) - $ / shares	May 03, 2018	Mar. 31, 2018	Mar. 31, 2017
Subsequent Event [Line Items]
Dividends, Common Stock, Cash		$ 0.33	$ 0.28
Dividend Declared | Subsequent Event
Subsequent Event [Line Items]
Dividends, Common Stock, Cash	$ 0.33