Cohen & Steers (CNS) 10-Q 8 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - shares	9 Months Ended
	Sep. 30, 2018	Nov. 05, 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	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		46,764,855

Condensed Consolidated Statemen

Condensed Consolidated Statements of Financial Condition (Unaudited) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents		$ 164,460	$ 193,452
Investments ($414), ($115,902 and $68,101)	[1],[2]	207,908	108,106
Accounts receivable		60,110	53,854
Due from brokers ($3,748 and $5,410)	[1]	6,250	6,429
Property and equipment—net		14,196	15,040
Goodwill and intangible assets—net		19,949	20,379
Deferred income tax assets—net		6,686	5,812
Other assets ($1,935 and $931)	[1]	8,626	7,053
Total assets		488,185	410,125
Liabilities:
Accrued compensation		31,693	41,370
Distribution and service fees payable		8,520	6,231
Income tax payable		18,953	19,892
Due to brokers ($3,793 and $3,203)	[1]	3,793	3,282
Deferred rent		5,863	5,994
Other liabilities and accrued expenses ($477 and $291)	[1]	10,294	10,025
Total liabilities		79,116	86,794
Commitments and contingencies
Redeemable noncontrolling interest		84,828	47,795
Stockholders’ equity:
Common stock, $0.01 par value; 500,000,000 shares authorized; 51,811,472 and 51,104,593 shares issued at September 30, 2018 and December 31, 2017, respectively		518	511
Additional paid-in capital		590,827	570,486
Accumulated deficit		(96,544)	(137,972)
Accumulated other comprehensive loss, net of tax		(6,143)	(3,671)
Less: Treasury stock, at cost, 5,050,285 and 4,789,608 shares at September 30, 2018 and December 31, 2017, respectively		(164,417)	(153,818)
Total stockholders’ equity		324,241	275,536
Total liabilities and stockholders’ equity		$ 488,185	$ 410,125
[1]	Asset and liability amounts in parentheses represent the aggregated balances at September 30, 2018 and December 31, 2017 attributable to variable interest entities consolidated by the Company. Refer to Note 4 for further discussion.
[2]	Pledged as collateral attributable to the consolidated balances of the Cohen & Steers Active Commodities Strategy Fund, Inc. at December 31, 2017.

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Financial Condition (Unaudited) Condensed Consolidated Statements of Financial Condition (Unaudited) (Parenthetical) - USD ($)		Sep. 30, 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		51,811,472	51,104,593
Treasury Stock, shares		5,050,285	4,789,608
Investments		$ 59,627,000	$ 74,856,000
Due from brokers	[1]	6,250,000	6,429,000
Other assets	[1]	8,626,000	7,053,000
Due to brokers	[1]	3,793,000	3,282,000
Other liabilities and accrued expenses	[1]	10,294,000	10,025,000
GLI SICAV, GRP-CIP and SICAV Preferred [Member]
Investments		115,902,000	68,101,000
Due from brokers		3,748,000	5,410,000
Other assets		1,935,000	931,000
Due to brokers		3,793,000	3,203,000
Other liabilities and accrued expenses		477,000	291,000
Trading investments pledged as collateral
Trading investments and pledged as collateral	[2]	$ 845,000	$ 414,000
[1]	Asset and liability amounts in parentheses represent the aggregated balances at September 30, 2018 and December 31, 2017 attributable to variable interest entities consolidated by the Company. Refer to Note 4 for further discussion.
[2]	Pledged as collateral attributable to the consolidated balances of the Cohen & Steers Active Commodities Strategy Fund, Inc. at December 31, 2017.

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	[1]	Sep. 30, 2018	Sep. 30, 2017	[1]
Revenue:
Total revenue	$ 98,331	$ 96,787		$ 287,205	$ 279,242
Expenses:
Employee compensation and benefits	33,126	31,886		96,788	91,681
Distribution and service fees	13,210	12,968		38,492	39,725
General and administrative	11,634	9,849		35,791	30,733
Depreciation	1,138	1,111		3,405	3,245
Total expenses	59,108	55,814		174,476	165,384
Operating income	39,223	40,973		112,729	113,858
Non-operating income (loss):
Interest and dividend income—net	2,747	1,425		7,434	2,710
Gain (loss) from investments—net	413	912		(4,692)	737
Foreign currency gains (losses)—net	(2,113)	(10)		(2,672)	(632)
Total non-operating income (loss)	1,047	2,327		70	2,815
Income before provision for income taxes	40,270	43,300		112,799	116,673
Provision for income taxes	10,539	17,562		28,575	44,993
Net income	29,731	25,738		84,224	71,680
Less: Net (income) loss attributable to redeemable noncontrolling interest	1,059	(656)		4,111	(139)
Net income attributable to common stockholders	$ 30,790	$ 25,082		$ 88,335	$ 71,541
Earnings per share attributable to common stockholders:
Basic (in dollars per share)	$ 0.66	$ 0.54		$ 1.89	$ 1.54
Diluted (in dollars per share)	0.65	0.53		1.87	1.53
Dividends declared per share (in dollars per share)	$ 0.33	$ 0.28		$ 0.99	$ 0.84
Weighted average shares outstanding:
Basic (shares)	46,830	46,386		46,778	46,335
Diluted (shares)	47,524	47,047		47,327	46,858
Investment advisory and administration fees
Revenue:
Total revenue	$ 88,150	$ 86,252		$ 257,004	$ 248,096
Distribution and service fees
Revenue:
Total revenue	7,451	7,808		22,108	22,867
Portfolio consulting and other
Revenue:
Total revenue	$ 2,730	$ 2,727		$ 8,093	$ 8,279
[1]	Certain amounts have been recast to reflect the Company's adoption of the new revenue recognition accounting standard on January 1, 2018. See Notes 2 and 3 for further discussion of the Company's recently adopted accounting pronouncements and revenue, respectively.

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income		$ 29,731	$ 25,738	[1]	$ 84,224	$ 71,680	[1]
Less: Net (income) loss attributable to redeemable noncontrolling interest		1,059	(656)	[1]	4,111	(139)	[1]
Net income attributable to common stockholders		30,790	25,082	[1]	88,335	71,541	[1]
Other comprehensive income, net of tax:
Foreign currency translation gain (loss)		(300)	551		(1,377)	1,925
Net unrealized gain (loss) from available-for-sale investments (net of tax of $0)	[2]	0	280		0	398
Reclassification to statements of operations of (gain) loss from available-for-sale investments		0	(235)		0	(353)
Other comprehensive income (loss)		(300)	596		(1,377)	1,970
Total comprehensive income attributable to common stockholders		$ 30,490	$ 25,678		$ 86,958	$ 73,511
[1]	Certain amounts have been recast to reflect the Company's adoption of the new revenue recognition accounting standard on January 1, 2018. See Notes 2 and 3 for further discussion of the Company's recently adopted accounting pronouncements and revenue, respectively.
[2]	Due to the adoption and application of the amendments to the financial instruments accounting standard on January 1, 2018, realized and unrealized gains (losses) from equity investments at fair value are recognized through earnings rather than through other comprehensive income. See Notes 2 and 4 for further discussion of the Company's recently adopted accounting pronouncements and investments, respectively.

Condensed Consolidated Statem_5

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					(40,225)			(40,225)
Issuance of common stock			$ 7	624				631
Issuance of common stock, shares			685
Repurchase of common stock							(9,141)	(9,141)
Repurchase of common stock, shares			(265)
Issuance of restricted stock units				1,749				1,749
Amortization of restricted stock units—net				16,626	(285)			16,341
Forfeitures of restricted stock units				(90)				(90)
Net income (loss)	$ 71,680	[1]			71,541			71,541	139
Other comprehensive income (loss), net of tax	1,970					1,970		1,970
Contributions from redeemable noncontrolling interest	(45,133)								45,133
Distributions to redeemable noncontrolling interest									(49)
Ending balance at Sep. 30, 2017			$ 511	562,738	(96,926)	(3,915)	(153,818)	308,590
Ending balance (redeemable noncontrolling interest) at Sep. 30, 2017									46,076
Ending balance (shares of common stock, net) at Sep. 30, 2017			46,310
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					(48,002)			(48,002)
Issuance of common stock			$ 7	592				599
Issuance of common stock, shares			707
Repurchase of common stock							(10,599)	(10,599)
Repurchase of common stock, shares			(261)
Issuance of restricted stock units				2,133				2,133
Amortization of restricted stock units—net				17,647	0			17,647
Forfeitures of restricted stock units				(31)				(31)
Net income (loss)	84,224				88,335			88,335	(4,111)
Other comprehensive income (loss), net of tax	(1,377)					(1,377)		(1,377)
Contributions from redeemable noncontrolling interest	(45,477)								45,477
Distributions to redeemable noncontrolling interest									(4,333)
Ending balance at Sep. 30, 2018	$ 324,241		$ 518	$ 590,827	$ (96,544)	$ (6,143)	$ (164,417)	$ 324,241
Ending balance (redeemable noncontrolling interest) at Sep. 30, 2018									$ 84,828
[1]	Certain amounts have been recast to reflect the Company's adoption of the new revenue recognition accounting standard on January 1, 2018. See Notes 2 and 3 for further discussion of the Company's recently adopted accounting pronouncements and revenue, respectively.

Condensed Consolidated Statem_6

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 84,224	$ 71,680	[1]
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Stock compensation expense	17,707	16,346
Amortization of deferred commissions	1,265	2,345
Depreciation and amortization	3,405	3,245
Deferred rent	(131)	(175)
Amortization (accretion) of premium (discount) on held-to-maturity investments	(97)	0
Gain (loss) from investments—net	4,692	(737)	[1]
Deferred income taxes	(873)	(1,133)
Foreign currency (gain) loss	756	78
Changes in operating assets and liabilities:
Accounts receivable	(7,012)	(16,131)
Due from brokers	179	(4,988)
Deferred commissions	(799)	(1,401)
Investments with consolidated funds	(54,842)	(61,125)
Other assets	(2,165)	(489)
Accrued compensation	(9,651)	(4,949)
Distribution and service fees payable	2,289	1,472
Due to brokers	511	3,738
Income tax payable	(939)	2,987
Other liabilities and accrued expenses	804	(118)
Net cash provided by (used in) operating activities	39,323	10,645
Cash flows from investing activities:
Net proceeds (purchase) from redemptions of equity method investments-net	37	(12)
Purchases of investments	(60,695)	(14,936)
Proceeds from sales of investments	11,144	24,172
Purchases of property and equipment	(2,504)	(2,441)
Net cash provided by (used in) investing activities	(52,018)	6,783
Cash flows from financing activities:
Issuance of common stock	509	536
Repurchase of common stock	(10,599)	(9,141)
Dividends to stockholders	(46,345)	(38,944)
Distributions to redeemable noncontrolling interest	(4,333)	(49)
Contributions from redeemable noncontrolling interest	45,477	45,133
Net cash provided by (used in) financing activities	(15,291)	(2,465)
Net increase (decrease) in cash and cash equivalents	(27,986)	14,963
Effect of foreign exchange rate changes on cash and cash equivalents	(1,006)	676
Cash and cash equivalents, beginning of the period	193,452	183,234
Cash and cash equivalents, end of the period	164,460	198,873
Amortization (accretion) of premium (discount) on held-to-maturity investments	$ (97)	$ 0
[1]	Certain amounts have been recast to reflect the Company's adoption of the new revenue recognition accounting standard on January 1, 2018. See Notes 2 and 3 for further discussion of the Company's recently adopted accounting pronouncements and revenue, respectively.

Condensed Consolidated Statem_7

Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Statement of Cash Flows [Abstract]
Income taxes paid, net	$ (30,344)	$ (43,188)
Fully vested restricted stock units issued	476	468
Restricted stock unit dividend equivalents, net of forfeitures	$ 1,657	$ 1,281

Organization and Description of

Organization and Description of Business	9 Months Ended
	Sep. 30, 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	9 Months Ended
	Sep. 30, 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 Financial Accounting Standards Board (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, among other items, distributions received from equity method investees. 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, among other items, equity investments as well as the presentation and disclosure requirements for financial instruments. 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. 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 periods presented (in thousands): Three Months Ended Nine Months Ended Previously Reported Net Adjustments Due to New Revenue Standard Recast Previously Reported Net Adjustments Due to New Revenue Standard Recast Revenue: Investment advisory and administration fees $ 88,557 $ (2,305 ) $ 86,252 $ 255,353 $ (7,257 ) $ 248,096 Distribution and service fees $ 5,070 $ 2,738 $ 7,808 $ 15,220 $ 7,647 $ 22,867 Expenses: Distribution and service fees (1) $ 9,575 $ 2,806 $ 12,381 $ 29,512 $ 7,868 $ 37,380 General and administrative $ 12,222 $ (2,373 ) $ 9,849 $ 38,211 $ (7,478 ) $ 30,733 ________________________ (1) The amount presented in the condensed consolidated statements of operations differs from the amount presented within this table due to the reclassification of certain amounts previously reported as depreciation and amortization. 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 disclosures 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 (ii) 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 September 30, 2018 , the Company's investments were comprised of the following: • Equity investments at fair value, which includes securities held within the affiliated funds that the Company consolidates, individual securities held directly for the purposes of establishing performance track records and seed investments in Company-sponsored open-end funds where the Company has neither control nor the ability to exercise significant influence. • Trading investments, which represent securities held within the affiliated funds that the Company consolidates and individual securities held directly for the purposes of establishing performance track records. • Held-to-maturity investments, which represent fixed income securities recorded at amortized cost. • Equity method investments, which 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. 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. 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 September 30, 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 foreign currency gains (losses)—net 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 are 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 and nine months ended September 30, 2018 and 2017, a portion of the distribution fee revenue recognized 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 are 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 on its 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 $(6,143,000) and $(4,781,000) as of September 30, 2018 and December 31, 2017 , respectively. Gains or losses resulting from transactions denominated in currencies other than U.S. dollars are included in other non-operating income (loss) in the condensed consolidated statements of operations. Gains and losses arising on revaluation of U.S. dollar-denominated assets and liabilities held by foreign subsidiaries are included in the Company’s condensed consolidated statements of operations. Comprehensive Income —The Company reports all changes in comprehensive income on 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 expects to adopt the new standard using the prospective method and does not expect the adoption 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 an 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 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. In July 2018, the FASB issued amendments to the guidance intended to provide supplemental narrow-scope improvements and clarifications. The new guidance, along with the amendments, is effective on January 1, 2019, with early adoption permitted. Furthermore, the Company is allowed the option of applying certain practical expedients and must apply the new guidance using a modified retrospective approach. 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. Lastly, the Company is still assessing which of the available practical expedients it plans to elect upon adoption.

Revenue

Revenue	9 Months Ended
	Sep. 30, 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 the periods presented (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Client domicile: North America $ 83,377 $ 80,583 $ 243,193 $ 230,249 Japan 8,951 10,415 26,927 32,325 Asia excluding Japan 3,263 2,990 9,356 8,422 Europe 2,740 2,799 7,729 8,246 Total $ 98,331 $ 96,787 $ 287,205 $ 279,242 Three Months Ended Nine Months Ended 2018 2017 2018 2017 Vehicle: Open-end funds (1) $ 49,882 $ 48,570 $ 145,112 $ 138,499 Closed-end funds 19,861 19,905 58,171 58,297 Institutional accounts 25,858 25,585 75,829 74,167 Portfolio consulting and other 2,730 2,727 8,093 8,279 Total $ 98,331 $ 96,787 $ 287,205 $ 279,242 ________________________ (1) Included distribution and service fees of $7.5 million and $7.8 million for three months ended September 30, 2018 and 2017, respectively, and $22.1 million and $22.9 million for the nine months ended September 30, 2018 and 2017, respectively.

Investments

Investments	9 Months Ended
	Sep. 30, 2018
Investments [Abstract]
Investments	Investments The following table summarizes the Company’s investments for the periods presented (in thousands): September 30, 2018 Equity investments at fair value $ 59,627 Trading 98,654 Held-to-maturity (1) 49,599 Equity method 28 Total investments $ 207,908 _________________________ (1) At September 30, 2018, held-to-maturity investments had an amortized cost of approximately $49.6 million and a fair value of approximately $49.5 million , with maturities ranging from 6 to 24 months. December 31, 2017 Trading $ 74,856 Equity method 6,176 Available-for-sale 27,074 Total investments $ 108,106 The Company seeded one new fund during the nine months ended September 30, 2018 and two new funds during the nine months ended September 30, 2017. The following tables summarize gain (loss) from investments for the periods presented (in thousands): Three Months Ended September 30, 2018 Nine Months Ended Gain (loss) from investments—net (1) Net realized gains (losses) during the period $ (278 ) $ (445 ) Net unrealized gains (losses) during the period on investments still held at the end of the period 691 (4,247 ) Gain (loss) from investments—net $ 413 $ (4,692 ) _________________________ (1) Included net income (loss) attributable to redeemable noncontrolling interest for the periods presented. Three Months Ended September 30, 2017 Nine Months Ended Gain (loss) from trading investments—net (1) $ 595 $ 870 Equity in earnings (losses) of affiliates—net 82 (486 ) Gain (loss) from available-for-sale investments—net 235 353 Total gain (loss) from investments $ 912 $ 737 _________________________ (1) Included net income (loss) attributable to redeemable noncontrolling interest for the periods presented. 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), the Cohen & Steers SICAV Global Preferred Securities Fund (SICAV Preferred) and the Cohen & Steers SICAV Diversified Real Assets Fund (SICAV RAP) for the periods presented (in thousands): September 30, 2018 GLI SICAV GRP-CIP SICAV Preferred SICAV RAP Total Assets (1) Investments $ 5,853 $ 574 $ 99,749 $ 9,726 $ 115,902 Due from brokers 233 118 2,747 650 3,748 Other assets 141 — 1,629 165 1,935 Total assets $ 6,227 $ 692 $ 104,125 $ 10,541 $ 121,585 Liabilities (1) Due to brokers $ 14 $ — $ 3,296 $ 483 $ 3,793 Other liabilities and accrued expenses 90 5 246 136 477 Total liabilities $ 104 $ 5 $ 3,542 $ 619 $ 4,270 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 is a summary of the cost, gross unrealized gains, gross unrealized losses and fair value of available-for-sale investments for the year ended December 31, 2017 (in thousands): 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 securities with 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 periods presented (in thousands): Three Months Ended September 30, 2017 Nine Months Ended Proceeds from sales $ 4,444 $ 24,354 Gross realized gains 336 650 Gross realized losses (101 ) (297 )

Fair Value

Fair Value	9 Months Ended
	Sep. 30, 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. If the asset or liability has a specified (contractual) term, the level 2 input must be observable for substantially the full term of the asset or liability. • 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. The following table presents fair value measurements as of September 30, 2018 (in thousands): Level 1 Level 2 Level 3 Investments Measured at NAV Investments Carried at Amortized Cost Total Cash equivalents $ 155,330 $ — $ — $ — $ — $ 155,330 Equity investments at fair value Common stocks $ 23,627 $ — $ — $ — $ — $ 23,627 Company-sponsored funds 11,486 — — — — 11,486 Limited partnership interests 1,444 — — 574 — 2,018 Preferred securities 20,529 1,853 — — — 22,382 Other — — — 114 — 114 Total $ 57,086 $ 1,853 $ — $ 688 $ — $ 59,627 Trading investments Fixed income $ 363 $ 98,291 $ — $ — $ — $ 98,654 Total $ 363 $ 98,291 $ — $ — $ — $ 98,654 Held-to-maturity investments Fixed income $ — $ — $ — $ — $ 49,599 $ 49,599 Total $ — $ — $ — $ — $ 49,599 $ 49,599 Equity method investments $ — $ — $ — $ 28 $ — $ 28 Total investments $ 57,449 $ 100,144 $ — $ 716 $ 49,599 $ 207,908 Derivatives - assets Commodity contracts $ 447 $ 22 $ — $ — $ — $ 469 Foreign exchange contracts — 741 — — — 741 Total $ 447 $ 763 $ — $ — $ — $ 1,210 Derivatives - liabilities Commodity contracts $ 596 $ — $ — $ — $ — $ 596 Total $ 596 $ — $ — $ — $ — $ 596 Cash equivalents were comprised of investments in actively traded U.S. Treasury money market funds measured at NAV. 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. Trading investments classified as level 2 in the above table were comprised of U.S. Treasury securities held within consolidated funds 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. Investments measured at NAV were comprised of certain investments measured at fair value using NAV (or its equivalent) as a practical expedient. These investments were comprised of: • Equity investments at fair value - limited partner interests in limited partnership vehicles that invest in non-registered real estate funds and the Company's co-investment in a Cayman trust invested in global listed infrastructure securities, both of which are valued based on the NAVs of the underlying investments. At September 30, 2018 , the Company did not have the ability to redeem the interests in the limited partnership vehicles; there were no contractual restrictions on the Company's ability to redeem its interest in the Cayman trust. • Equity method investments - 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 September 30, 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 September 30, 2018 , the Company did not have the ability to redeem this investment. Held-to-maturity investments were comprised of U.S. Treasury securities held by the Company, which were directly issued by the U.S. government. These securities were purchased with the intent to hold to maturity and are recorded at amortized cost. Investments measured at NAV and held-to-maturity investments have not been classified in the fair value hierarchy. The 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. The following table presents fair value measurements as of 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 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. Trading investments in fixed income securities classified as level 2 in the above table were comprised of U.S. Treasury securities 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 a limited partner interest in a limited partnership vehicle that invested in a private equity vehicle that invested directly in real estate which was valued using a contractual selling price. 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. 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. These investments were comprised of: • Trading investments - limited partner 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 - the Company's 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 - the Company's co-investment in a Cayman trust invested in global listed infrastructure securities. There were no contractual restrictions on the Company's ability to redeem this investment. 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 Nine Months Ended 2018 2017 2018 2017 Trading Investments Limited Partnership Interests Balance at beginning of the period $ — $ 1,462 $ 605 $ 1,196 Purchases / contributions — 281 — 419 Sales / distributions — — (598 ) — Realized gains (losses) — — (68 ) — Unrealized gains (losses) — (286 ) (1) 61 (158 ) (1) Transfers into (out of) level 3 — — — — Balance at end of the period $ — $ 1,457 $ — $ 1,457 _________________________ (1) Pertains to unrealized gains (losses) from investments still held at September 30, 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	9 Months Ended
	Sep. 30, 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 of all outstanding derivative contracts for the periods presented (in thousands): September 30, 2018 Assets Liabilities Notional Fair Value Notional Fair Value Commodity contracts $ 21,372 $ 469 $ 13,004 $ 596 Foreign exchange contracts 18,367 741 — — Total derivatives $ 39,739 $ 1,210 $ 13,004 $ 596 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 Cash included in due from broker on the condensed consolidated statement of financial condition of approximately $883,000 at September 30, 2018 was held as collateral for futures contracts. Investments on the condensed consolidated statements of financial condition of approximately $845,000 and $414,000 at September 30, 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 Nine Months Ended 2018 2017 2018 2017 Commodity contracts $ (186 ) $ 124 $ (193 ) $ (732 ) Foreign exchange contracts 414 136 805 (1,198 ) Total $ 228 $ 260 $ 612 $ (1,930 )

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 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. There were no anti-dilutive common stock equivalents for both the three months ended September 30, 2018 and 2017, as well as for the nine months ended September 30, 2018 . Anti-dilutive common stock equivalents of approximately 5,000 shares were excluded from the computation for the nine months ended September 30, 2017. 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 Nine Months Ended 2018 2017 2018 2017 Net income $ 29,731 $ 25,738 $ 84,224 $ 71,680 Less: Net (income) loss attributable to redeemable noncontrolling interest 1,059 (656 ) 4,111 (139 ) Net income attributable to common stockholders $ 30,790 $ 25,082 $ 88,335 $ 71,541 Basic weighted average shares outstanding 46,830 46,386 46,778 46,335 Dilutive potential shares from restricted stock units 694 661 549 523 Diluted weighted average shares outstanding 47,524 47,047 47,327 46,858 Basic earnings per share attributable to common stockholders $ 0.66 $ 0.54 $ 1.89 $ 1.54 Diluted earnings per share attributable to common stockholders $ 0.65 $ 0.53 $ 1.87 $ 1.53

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 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 September 30, 2018 was approximately 25.5% , compared with 41.2% for the three months ended September 30, 2017 . The effective tax rate for the three months ended September 30, 2018 differed from the U.S. federal statutory rate of 21% primarily due to state and local taxes. The effective tax rate for the three months ended September 30, 2017 differed from the U.S. federal statutory rate of 35% primarily due to state and foreign taxes as well as the cumulative effect of a change in the Company’s estimated effective tax rate for the year. The effective tax rate for the nine months ended September 30, 2018 was approximately 24.4% , compared with 38.6% for the nine months ended September 30, 2017 . The effective tax rate for the nine months ended September 30, 2018 differed from the U.S. federal statutory rate of 21% primarily due to state, local and foreign taxes, partially offset by tax benefits related to the delivery of restricted stock units and an adjustment to the Company's transition tax liability in connection with the Tax Cuts and Jobs Act. The effective tax rate for the nine months ended September 30, 2017 differed from the U.S. federal statutory rate of 35% primarily due to state and foreign taxes as well as the release of certain tax reserves. 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. In connection with the enactment of the Tax Cuts and Jobs Act, the Company recorded a provisional transition tax at December 31, 2017, which reflected a one-time tax on deemed repatriated accumulated earnings and profits of the Company’s foreign subsidiaries. The transition tax, which is payable over eight years on an interest-free basis, was included as part of income tax payable on the Company's condensed consolidated statements of financial condition at September 30, 2018 and December 31, 2017. Based on refinement of the calculation, the Company adjusted its transition tax liability from $8.4 million at December 31, 2017 to $8.3 million during the second quarter of 2018. On August 1, 2018, the U.S. Department of the Treasury and the Internal Revenue Service issued proposed regulations related to the calculation of the transition tax liability. Based on the Company’s preliminary assessment of the proposed regulations, it does not expect to make any material adjustments to its transition tax liability. However, this could change once the proposed regulations become finalized.

Regulatory Requirements

Regulatory Requirements	9 Months Ended
	Sep. 30, 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 September 30, 2018 , CSS had net capital of approximately $3.3 million , which exceeded its requirements by approximately $3.1 million . 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 is subject to regulation by the Hong Kong Securities and Futures Commission. At September 30, 2018, CSAL had regulatory capital of approximately $25.4 million , which exceeded its minimum regulatory capital requirements by approximately $25.0 million . During the three months ended September 30, 2018, CSAL paid a dividend in the amount of approximately $32.0 million to its parent, Cohen & Steers Capital Management, Inc. CSUK is subject to regulation by the United Kingdom Financial Conduct Authority. At September 30, 2018 , CSUK had regulatory capital of approximately $33.8 million , which exceeded its minimum regulatory capital requirements by approximately $29.1 million .

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 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 Nine Months Ended 2018 2017 2018 2017 Investment advisory and administration fees (1) $ 62,474 $ 60,757 $ 181,368 $ 174,199 Distribution and service fees 7,451 7,808 22,108 22,867 Total $ 69,925 $ 68,565 $ 203,476 $ 197,066 _________________________ (1) Investment advisory and administration fees are reflected net of fund reimbursements of approximately $2.1 million and $2.0 million for the three months ended September 30, 2018 and 2017, respectively, and approximately $6.4 million and $6.2 million for the nine months ended September 30, 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 Nine Months Ended 2018 2017 2018 2017 Proceeds from sales $ 3,053 $ — $ 10,782 $ 15,105 Gross realized gains 28 — 28 80 Gross realized losses (1 ) — (4,448 ) — Dividend income 102 141 369 529 Included in accounts receivable at September 30, 2018 and December 31, 2017 are receivables due from Company-sponsored funds of approximately $23,028,000 and $23,666,000 , respectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Rent expense charged to operations, including escalation charges for real estate and other expenses, totaled approximately $3.0 million and $3.2 million for the three months ended September 30, 2018 and 2017 , respectively, and approximately $8.8 million for both the nine months ended September 30, 2018 and 2017 . From time to time, the Company is involved in legal matters relating to claims arising in the ordinary course of business. At September 30, 2018 , there are no matters pending that the Company believes could have a material adverse effect on its condensed consolidated statements 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. (GRP-CIP) for up to 12 years through the life of GRP-TE. At September 30, 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 and GRP-CIP invest. At September 30, 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	9 Months Ended
	Sep. 30, 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	9 Months Ended
	Sep. 30, 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 November 7, 2018, the Company declared quarterly and special cash dividends on its common stock in the amount of $0.33 and $2.50 per share, respectively. The dividends will be payable on December 3, 2018 to stockholders of record at the close of business on November 19, 2018.

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements —In May 2017, the Financial Accounting Standards Board (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, among other items, distributions received from equity method investees. 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, among other items, equity investments as well as the presentation and disclosure requirements for financial instruments. 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. 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 periods presented (in thousands): Three Months Ended Nine Months Ended Previously Reported Net Adjustments Due to New Revenue Standard Recast Previously Reported Net Adjustments Due to New Revenue Standard Recast Revenue: Investment advisory and administration fees $ 88,557 $ (2,305 ) $ 86,252 $ 255,353 $ (7,257 ) $ 248,096 Distribution and service fees $ 5,070 $ 2,738 $ 7,808 $ 15,220 $ 7,647 $ 22,867 Expenses: Distribution and service fees (1) $ 9,575 $ 2,806 $ 12,381 $ 29,512 $ 7,868 $ 37,380 General and administrative $ 12,222 $ (2,373 ) $ 9,849 $ 38,211 $ (7,478 ) $ 30,733 ________________________ (1) The amount presented in the condensed consolidated statements of operations differs from the amount presented within this table due to the reclassification of certain amounts previously reported as depreciation and amortization.
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 disclosures 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 (ii) 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 September 30, 2018 , the Company's investments were comprised of the following: • Equity investments at fair value, which includes securities held within the affiliated funds that the Company consolidates, individual securities held directly for the purposes of establishing performance track records and seed investments in Company-sponsored open-end funds where the Company has neither control nor the ability to exercise significant influence. • Trading investments, which represent securities held within the affiliated funds that the Company consolidates and individual securities held directly for the purposes of establishing performance track records. • Held-to-maturity investments, which represent fixed income securities recorded at amortized cost. • Equity method investments, which 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. 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. 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 September 30, 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 foreign currency gains (losses)—net 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.
Investment Advisory and Administration Fees	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 are 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 —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 and nine months ended September 30, 2018 and 2017, a portion of the distribution fee revenue recognized 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 are 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	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 —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	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 on its 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 $(6,143,000) and $(4,781,000) as of September 30, 2018 and December 31, 2017 , respectively. Gains or losses resulting from transactions denominated in currencies other than U.S. dollars 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 on 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 expects to adopt the new standard using the prospective method and does not expect the adoption 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 an 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 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. In July 2018, the FASB issued amendments to the guidance intended to provide supplemental narrow-scope improvements and clarifications. The new guidance, along with the amendments, is effective on January 1, 2019, with early adoption permitted. Furthermore, the Company is allowed the option of applying certain practical expedients and must apply the new guidance using a modified retrospective approach. 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. Lastly, 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 Sig_3

Basis of Presentation and Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]	The adoption of the new revenue recognition standard resulted in the following changes to the Company's previously reported results for the periods presented (in thousands): Three Months Ended Nine Months Ended Previously Reported Net Adjustments Due to New Revenue Standard Recast Previously Reported Net Adjustments Due to New Revenue Standard Recast Revenue: Investment advisory and administration fees $ 88,557 $ (2,305 ) $ 86,252 $ 255,353 $ (7,257 ) $ 248,096 Distribution and service fees $ 5,070 $ 2,738 $ 7,808 $ 15,220 $ 7,647 $ 22,867 Expenses: Distribution and service fees (1) $ 9,575 $ 2,806 $ 12,381 $ 29,512 $ 7,868 $ 37,380 General and administrative $ 12,222 $ (2,373 ) $ 9,849 $ 38,211 $ (7,478 ) $ 30,733 ________________________ (1) The amount presented in the condensed consolidated statements of operations differs from the amount presented within this table due to the reclassification of certain amounts previously reported as depreciation and amortization.

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 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 the periods presented (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Client domicile: North America $ 83,377 $ 80,583 $ 243,193 $ 230,249 Japan 8,951 10,415 26,927 32,325 Asia excluding Japan 3,263 2,990 9,356 8,422 Europe 2,740 2,799 7,729 8,246 Total $ 98,331 $ 96,787 $ 287,205 $ 279,242 Three Months Ended Nine Months Ended 2018 2017 2018 2017 Vehicle: Open-end funds (1) $ 49,882 $ 48,570 $ 145,112 $ 138,499 Closed-end funds 19,861 19,905 58,171 58,297 Institutional accounts 25,858 25,585 75,829 74,167 Portfolio consulting and other 2,730 2,727 8,093 8,279 Total $ 98,331 $ 96,787 $ 287,205 $ 279,242 ________________________ (1) Included distribution and service fees of $7.5 million and $7.8 million for three months ended September 30, 2018 and 2017, respectively, and $22.1 million and $22.9 million for the nine months ended September 30, 2018 and 2017, respectively.

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2018
Investments [Abstract]
Summary Investment Holdings	The following table summarizes the Company’s investments for the periods presented (in thousands): September 30, 2018 Equity investments at fair value $ 59,627 Trading 98,654 Held-to-maturity (1) 49,599 Equity method 28 Total investments $ 207,908 _________________________ (1) At September 30, 2018, held-to-maturity investments had an amortized cost of approximately $49.6 million and a fair value of approximately $49.5 million , with maturities ranging from 6 to 24 months. December 31, 2017 Trading $ 74,856 Equity method 6,176 Available-for-sale 27,074 Total investments $ 108,106
Gain (Loss) on Investments	he following tables summarize gain (loss) from investments for the periods presented (in thousands): Three Months Ended September 30, 2018 Nine Months Ended Gain (loss) from investments—net (1) Net realized gains (losses) during the period $ (278 ) $ (445 ) Net unrealized gains (losses) during the period on investments still held at the end of the period 691 (4,247 ) Gain (loss) from investments—net $ 413 $ (4,692 ) _________________________ (1) Included net income (loss) attributable to redeemable noncontrolling interest for the periods presented. Three Months Ended September 30, 2017 Nine Months Ended Gain (loss) from trading investments—net (1) $ 595 $ 870 Equity in earnings (losses) of affiliates—net 82 (486 ) Gain (loss) from available-for-sale investments—net 235 353 Total gain (loss) from investments $ 912 $ 737 _________________________ (1) Included net income (loss) attributable to redeemable noncontrolling interest for the periods presented.
Schedule of Variable Interest Entities	presented (in thousands): September 30, 2018 GLI SICAV GRP-CIP SICAV Preferred SICAV RAP Total Assets (1) Investments $ 5,853 $ 574 $ 99,749 $ 9,726 $ 115,902 Due from brokers 233 118 2,747 650 3,748 Other assets 141 — 1,629 165 1,935 Total assets $ 6,227 $ 692 $ 104,125 $ 10,541 $ 121,585 Liabilities (1) Due to brokers $ 14 $ — $ 3,296 $ 483 $ 3,793 Other liabilities and accrued expenses 90 5 246 136 477 Total liabilities $ 104 $ 5 $ 3,542 $ 619 $ 4,270 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.
Schedule of Available-for-sale Investments Reconciliation	The following is a summary of the cost, gross unrealized gains, gross unrealized losses and fair value of available-for-sale investments for the year ended December 31, 2017 (in thousands): 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 securities with unrealized losses continuously for a period of more than 12 months.
Realized Gain (Loss) on Investments	he following table summarizes sales proceeds, gross realized gains and losses from available-for-sale investments for the periods presented (in thousands): Three Months Ended September 30, 2017 Nine Months Ended Proceeds from sales $ 4,444 $ 24,354 Gross realized gains 336 650 Gross realized losses (101 ) (297 )

Fair Value (Tables)

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements, Recurring and Nonrecurring	The following table presents fair value measurements as of 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 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 as of September 30, 2018 (in thousands): Level 1 Level 2 Level 3 Investments Measured at NAV Investments Carried at Amortized Cost Total Cash equivalents $ 155,330 $ — $ — $ — $ — $ 155,330 Equity investments at fair value Common stocks $ 23,627 $ — $ — $ — $ — $ 23,627 Company-sponsored funds 11,486 — — — — 11,486 Limited partnership interests 1,444 — — 574 — 2,018 Preferred securities 20,529 1,853 — — — 22,382 Other — — — 114 — 114 Total $ 57,086 $ 1,853 $ — $ 688 $ — $ 59,627 Trading investments Fixed income $ 363 $ 98,291 $ — $ — $ — $ 98,654 Total $ 363 $ 98,291 $ — $ — $ — $ 98,654 Held-to-maturity investments Fixed income $ — $ — $ — $ — $ 49,599 $ 49,599 Total $ — $ — $ — $ — $ 49,599 $ 49,599 Equity method investments $ — $ — $ — $ 28 $ — $ 28 Total investments $ 57,449 $ 100,144 $ — $ 716 $ 49,599 $ 207,908 Derivatives - assets Commodity contracts $ 447 $ 22 $ — $ — $ — $ 469 Foreign exchange contracts — 741 — — — 741 Total $ 447 $ 763 $ — $ — $ — $ 1,210 Derivatives - liabilities Commodity contracts $ 596 $ — $ — $ — $ — $ 596 Total $ 596 $ — $ — $ — $ — $ 596
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 Nine Months Ended 2018 2017 2018 2017 Trading Investments Limited Partnership Interests Balance at beginning of the period $ — $ 1,462 $ 605 $ 1,196 Purchases / contributions — 281 — 419 Sales / distributions — — (598 ) — Realized gains (losses) — — (68 ) — Unrealized gains (losses) — (286 ) (1) 61 (158 ) (1) Transfers into (out of) level 3 — — — — Balance at end of the period $ — $ 1,457 $ — $ 1,457 _________________________ (1) Pertains to unrealized gains (losses) from investments still held at September 30, 2017.

Derivatives (Tables)

Derivatives (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	The following tables summarize the notional and fair value of the derivative financial instruments. The notional amount represents the absolute value of all outstanding derivative contracts for the periods presented (in thousands): September 30, 2018 Assets Liabilities Notional Fair Value Notional Fair Value Commodity contracts $ 21,372 $ 469 $ 13,004 $ 596 Foreign exchange contracts 18,367 741 — — Total derivatives $ 39,739 $ 1,210 $ 13,004 $ 596 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
Gains (losses) on Derivatives	Three Months Ended Nine Months Ended 2018 2017 2018 2017 Commodity contracts $ (186 ) $ 124 $ (193 ) $ (732 ) Foreign exchange contracts 414 136 805 (1,198 ) Total $ 228 $ 260 $ 612 $ (1,930 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 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 Nine Months Ended 2018 2017 2018 2017 Net income $ 29,731 $ 25,738 $ 84,224 $ 71,680 Less: Net (income) loss attributable to redeemable noncontrolling interest 1,059 (656 ) 4,111 (139 ) Net income attributable to common stockholders $ 30,790 $ 25,082 $ 88,335 $ 71,541 Basic weighted average shares outstanding 46,830 46,386 46,778 46,335 Dilutive potential shares from restricted stock units 694 661 549 523 Diluted weighted average shares outstanding 47,524 47,047 47,327 46,858 Basic earnings per share attributable to common stockholders $ 0.66 $ 0.54 $ 1.89 $ 1.54 Diluted earnings per share attributable to common stockholders $ 0.65 $ 0.53 $ 1.87 $ 1.53

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 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 Nine Months Ended 2018 2017 2018 2017 Investment advisory and administration fees (1) $ 62,474 $ 60,757 $ 181,368 $ 174,199 Distribution and service fees 7,451 7,808 22,108 22,867 Total $ 69,925 $ 68,565 $ 203,476 $ 197,066 _________________________ (1) Investment advisory and administration fees are reflected net of fund reimbursements of approximately $2.1 million and $2.0 million for the three months ended September 30, 2018 and 2017, respectively, and approximately $6.4 million and $6.2 million for the nine months ended September 30, 2018 and 2017 , respectively.
Schedule of Realized Gain (Loss)	Three Months Ended Nine Months Ended 2018 2017 2018 2017 Proceeds from sales $ 3,053 $ — $ 10,782 $ 15,105 Gross realized gains 28 — 28 80 Gross realized losses (1 ) — (4,448 ) — Dividend income 102 141 369 529

Basis of Presentation and Sig_4

Basis of Presentation and Significant Accounting Policies (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accumulated Translation Adjustment
Cumulative Translation Adjustments balance [Line Items]
Cumulative Foreign Currency Translation Adjustment, Net of Tax	$ (6,143)	$ (4,781)

Basis of Presentation and Sig_5

Basis of Presentation and Significant Accounting Policies New Accountings Pronouncements (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018	Sep. 30, 2017		Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenue	$ 98,331,000	$ 96,787,000	[1]	$ 287,205,000	$ 279,242,000	[1]
Distribution and service fees	13,210,000	12,968,000	[1]	38,492,000	39,725,000	[1]
General and administrative	11,634,000	9,849,000	[1]	35,791,000	30,733,000	[1]
Cumulative effect of new accounting principle	(96,544,000)			(96,544,000)				$ (137,972,000)
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Distribution and service fees		12,381,000			37,380,000
General and administrative		9,849,000			30,733,000
Net Adjustments Due to New Revenue Standard | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Distribution and service fees		2,806,000			7,868,000
General and administrative		(2,373,000)			(7,478,000)
Net Adjustments Due to New Revenue Standard | Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle							$ 1,095,000
Previously Reported | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Distribution and service fees		9,575,000			29,512,000
General and administrative		12,222,000			38,211,000
Investment advisory and administration fees
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenue	88,150,000	86,252,000	[1]	257,004,000	248,096,000	[1]
Investment advisory and administration fees | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenue		86,252,000			248,096,000
Investment advisory and administration fees | Net Adjustments Due to New Revenue Standard | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenue		(2,305,000)			(7,257,000)
Investment advisory and administration fees | Previously Reported | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenue		88,557,000			255,353,000
Distribution and service fees
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenue	$ 7,451,000	7,808,000	[1]	$ 22,108,000	22,867,000	[1]
Distribution and service fees | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenue		7,808,000			22,867,000
Distribution and service fees | Net Adjustments Due to New Revenue Standard | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenue		2,738,000			7,647,000
Distribution and service fees | Previously Reported | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenue		$ 5,070,000			$ 15,220,000
[1]	Certain amounts have been recast to reflect the Company's adoption of the new revenue recognition accounting standard on January 1, 2018. See Notes 2 and 3 for further discussion of the Company's recently adopted accounting pronouncements and revenue, respectively.

Revenue (Details)

Revenue (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 98,331	$ 96,787	[1]	$ 287,205	$ 279,242	[1]
Portfolio consulting and other
Disaggregation of Revenue [Line Items]
Revenues	2,730	2,727		8,093	8,279
Institutional accounts | Vehicles:
Disaggregation of Revenue [Line Items]
Revenues	25,858	25,585		75,829	74,167
Open-end funds | Vehicles:
Disaggregation of Revenue [Line Items]
Revenues	49,882	48,570		145,112	138,499
Close-end funds | Vehicles:
Disaggregation of Revenue [Line Items]
Revenues	19,861	19,905		58,171	58,297
North America
Disaggregation of Revenue [Line Items]
Revenues	83,377	80,583		243,193	230,249
Japan
Disaggregation of Revenue [Line Items]
Revenues	8,951	10,415		26,927	32,325
Asia excluding Japan
Disaggregation of Revenue [Line Items]
Revenues	3,263	2,990		9,356	8,422
Europe
Disaggregation of Revenue [Line Items]
Revenues	2,740	2,799		7,729	8,246
Investment advisory and administration fees
Disaggregation of Revenue [Line Items]
Revenues	88,150	86,252	[1]	257,004	248,096	[1]
Investment advisory and administration fees | Open-end funds | Vehicles:
Disaggregation of Revenue [Line Items]
Revenues	$ 7,500	$ 7,800		$ 22,100	$ 22,900
[1]	Certain amounts have been recast to reflect the Company's adoption of the new revenue recognition accounting standard on January 1, 2018. See Notes 2 and 3 for further discussion of the Company's recently adopted accounting pronouncements and revenue, respectively.

Investments Trading and Equity

Investments Trading and Equity Investments (Details) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)		Sep. 30, 2018USD ($)new_funds_seeded	Sep. 30, 2017USD ($)new_funds_seeded		Dec. 31, 2017USD ($)
Trading Securities and Other Trading Assets [Line Items]
Number of new funds seeded | new_funds_seeded					1	2
Investments		$ 59,627			$ 59,627			$ 74,856
Trading Securities, Debt		98,654			98,654
Held-to-maturity Securities	[1]	49,599			49,599
Equity method investments		28			28			6,176
Available-for-sale investments								27,074
Investments	[2],[3]	207,908			207,908			$ 108,106
Gain (Loss) on Investments [Abstract]
Net realized gains (losses) during the period	[4]	(278)			(445)
Net unrealized gains (losses) during the period on investments still held at the end of the period		691			(4,247)
Gain (loss) from trading investments—net	[4]		$ 595			$ 870
Equity in earnings (losses) of affiliates—net			82			(486)
Gain (loss) from available-for-sale investments—net			235			353
Total gain (loss) from investments—net		$ 413	$ 912	[5]	$ (4,692)	$ 737	[5]
[1]	At September 30, 2018, held-to-maturity investments had an amortized cost of approximately $49.6 million and a fair value of approximately $49.5 million, with maturities ranging from 6 to 24 months.
[2]	Asset and liability amounts in parentheses represent the aggregated balances at September 30, 2018 and December 31, 2017 attributable to variable interest entities consolidated by the Company. Refer to Note 4 for further discussion.
[3]	Pledged as collateral attributable to the consolidated balances of the Cohen & Steers Active Commodities Strategy Fund, Inc. at December 31, 2017.
[4]	ncluded net income (loss) attributable to redeemable noncontrolling interest for the periods presented.
[5]	Certain amounts have been recast to reflect the Company's adoption of the new revenue recognition accounting standard on January 1, 2018. See Notes 2 and 3 for further discussion of the Company's recently adopted accounting pronouncements and revenue, respectively.

Investments Variable Interest E

Investments Variable Interest Entity (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Investments	[1],[2]	$ 207,908	$ 108,106
Due from brokers	[1]	6,250	6,429
Other assets	[1]	8,626	7,053
Assets		488,185	410,125
Due to brokers	[1]	3,793	3,282
Other liabilities and accrued expenses	[1]	10,294	10,025
Liabilities		79,116	86,794
GLI SICAV
Variable Interest Entity [Line Items]
Investments		5,853	5,961
Due from brokers		233	285
Other assets		141	32
Assets		6,227	6,278
Due to brokers		14	35
Other liabilities and accrued expenses		90	87
Liabilities		104	122
GRP-CIP
Variable Interest Entity [Line Items]
Investments		574	1,330
Due from brokers		118	202
Other assets		0	0
Assets		692	1,532
Due to brokers		0	0
Other liabilities and accrued expenses		5	5
Liabilities		5	5
SICAV Preferred
Variable Interest Entity [Line Items]
Investments		99,749	60,810
Due from brokers		2,747	4,923
Other assets		1,629	899
Assets		104,125	66,632
Due to brokers		3,296	3,168
Other liabilities and accrued expenses		246	199
Liabilities		3,542	3,367
SICAV RAP
Variable Interest Entity [Line Items]
Investments		9,726
Due from brokers		650
Other assets		165
Assets		10,541
Due to brokers		483
Other liabilities and accrued expenses		136
Liabilities		619
GLI SICAV, GRP-CIP and SICAV Preferred [Member]
Variable Interest Entity [Line Items]
Investments		115,902	68,101
Due from brokers		3,748	5,410
Other assets		1,935	931
Assets		121,585	74,442
Due to brokers		3,793	3,203
Other liabilities and accrued expenses		477	291
Liabilities		$ 4,270	$ 3,494
[1]	Asset and liability amounts in parentheses represent the aggregated balances at September 30, 2018 and December 31, 2017 attributable to variable interest entities consolidated by the Company. Refer to Note 4 for further discussion.
[2]	Pledged as collateral attributable to the consolidated balances of the Cohen & Steers Active Commodities Strategy Fund, Inc. at December 31, 2017.

Investments Available-for-Sale

Investments Available-for-Sale Invsetments (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
		Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2017
Available-for-sale Investments [Abstract]
Cost				$ 25,324
Gross Unrealized Gains				1,971
Gross Unrealized Losses	[1]			(221)
Fair Value				27,074
Available-for-sale investments in an unrealized loss position				6,086
Proceeds from Investing Activities [Abstract]
Proceeds from sales		$ 4,444	$ 24,354
Gross realized gains		336	650
Gross realized losses		$ (101)	$ (297)
Preferred securities
Available-for-sale Investments [Abstract]
Cost				1,100
Gross Unrealized Gains				29
Gross Unrealized Losses	[1]			(5)
Fair Value				1,124
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				(13)
Fair Value				14,632
Fixed income
Available-for-sale Investments [Abstract]
Cost				3,966
Gross Unrealized Gains				15
Gross Unrealized Losses				(20)
Fair Value				3,961
Other
Available-for-sale Investments [Abstract]
Cost				100
Gross Unrealized Gains				19
Gross Unrealized Losses				0
Fair Value				$ 119
[1]	t December 31, 2017, there were no securities with unrealized losses continuously for a period of more than 12 months.

Investments Held-to-maturity in

Investments Held-to-maturity investments (Details) $ in Millions	Sep. 30, 2018USD ($)
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	$ 49.6
Held-to-maturity investments	$ 49.5

Fair Value (Details)

Fair Value (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		$ 59,627		$ 59,627		$ 74,856
Available-for-sale investments						27,074
Held-to-maturity investments		49,500		49,500
Equity method investments		28		28		6,176
Available-for-sale investments						25,324
Investments	[1],[2]	207,908		207,908		108,106
Investments Measured at NAV		688		688		725
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment		49,600		49,600
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		59,627		59,627		74,856
Equity method investments						6,176
Available-for-sale investments						27,074
Investments		207,908		207,908
Investments Measured at NAV						119
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		57,086		57,086		13,619
Equity method investments						0
Available-for-sale investments						22,869
Investments		57,449		57,449
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		1,853		1,853		59,907
Equity method investments						0
Available-for-sale investments						4,086
Investments		100,144		100,144
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		0		0		605
Equity method investments						0
Available-for-sale investments						0
Investments		0		0
Company-sponsored funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0		0
Preferred securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0		0
Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		114		114		119
Fixed income
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		574		574		725
Common stocks
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0		0
Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0		0
Cash equivalents | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Cash equivalents		155,330		155,330		173,270
Cash equivalents | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Cash equivalents		155,330		155,330		173,270
Cash equivalents | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Cash equivalents		0		0		0
Cash equivalents | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Cash equivalents		0		0		0
Equity method investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		28		28		6,176
Equity method investments | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Equity method investments		28		28
Equity method investments | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Equity method investments		0		0
Equity method investments | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Equity method investments		0		0
Equity method investments | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Equity method investments		0		0
Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		716		716
Investments | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		49,599		49,599
Available-for-sale investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0
Available-for-sale investments | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		98,654		98,654
Investments						108,106
Investments Measured at NAV						7,020
Available-for-sale investments | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		363		363
Investments						36,488
Available-for-sale investments | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		98,291		98,291
Investments						63,993
Available-for-sale investments | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		0		0
Investments						605
Held-to-maturity investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0
Held-to-maturity investments | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment		49,599		49,599
Held-to-maturity investments | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Held-to-maturity investments		0		0
Held-to-maturity investments | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Held-to-maturity investments		0		0
Held-to-maturity investments | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Held-to-maturity investments		0		0
Derivative - assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0		0
Derivative - assets | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0		0
Derivative - assets | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0
Derivative - assets | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		1,210		1,210		487
Derivative - assets | Fair Value, Measurements, Recurring | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		469		469		487
Derivative - assets | Fair Value, Measurements, Recurring | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		741		741
Derivative - assets | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		447		447		487
Derivative - assets | Fair Value, Measurements, Recurring | Level 1 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		447		447		487
Derivative - assets | Fair Value, Measurements, Recurring | Level 1 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		0		0
Derivative - assets | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		763		763		0
Derivative - assets | Fair Value, Measurements, Recurring | Level 2 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		22		22		0
Derivative - assets | Fair Value, Measurements, Recurring | Level 2 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		741		741
Derivative - assets | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		0		0		0
Derivative - assets | Fair Value, Measurements, Recurring | Level 3 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - assets		0		0		0
Derivative - assets | 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
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0		0
Derivative - liabilities | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0		0
Derivative - liabilities | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV						0
Derivative - liabilities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities		596		596		350
Derivative - liabilities | Fair Value, Measurements, Recurring | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities		596		596		286
Derivative - liabilities | Fair Value, Measurements, Recurring | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities						64
Derivative - liabilities | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities		596		596		286
Derivative - liabilities | Fair Value, Measurements, Recurring | Level 1 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities		596		596		286
Derivative - liabilities | Fair Value, Measurements, Recurring | Level 1 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities						0
Derivative - liabilities | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities		0		0		64
Derivative - liabilities | Fair Value, Measurements, Recurring | Level 2 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities		0		0		0
Derivative - liabilities | Fair Value, Measurements, Recurring | Level 2 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities						64
Derivative - liabilities | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities		0		0		0
Derivative - liabilities | Fair Value, Measurements, Recurring | Level 3 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities		0		0		0
Derivative - liabilities | Fair Value, Measurements, Recurring | Level 3 | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative - liabilities						0
Fixed income
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments						3,966
Fixed income | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments						6,755
Available-for-sale investments						3,961
Fixed income | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments						0
Available-for-sale investments						0
Fixed income | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments						6,755
Available-for-sale investments						3,961
Fixed income | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments						0
Available-for-sale investments						0
Fixed income | Available-for-sale investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0
Fixed income | Available-for-sale investments | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		98,654		98,654
Fixed income | Available-for-sale investments | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		363		363
Fixed income | Available-for-sale investments | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		98,291		98,291
Fixed income | Available-for-sale investments | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		0		0
Fixed income | Held-to-maturity investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments Measured at NAV		0		0
Fixed income | Held-to-maturity investments | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment		49,599		49,599
Fixed income | Held-to-maturity investments | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Held-to-maturity investments		0		0
Fixed income | Held-to-maturity investments | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Held-to-maturity investments		0		0
Fixed income | Held-to-maturity investments | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Held-to-maturity investments		0		0
Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments						100
Other | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments						119
Other | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments						0
Other | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments						0
Other | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments						0
Other | Other | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments		114		114
Other | Other | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments		0		0
Other | Other | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments		0		0
Other | Other | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments		0		0
Preferred securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments						1,100
Preferred securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		22,382		22,382		60,810
Available-for-sale investments						1,124
Preferred securities | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		20,529		20,529		7,658
Available-for-sale investments						999
Preferred securities | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		1,853		1,853		53,152
Available-for-sale investments						125
Preferred securities | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		0		0		0
Available-for-sale investments						0
Limited partnership interests | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		2,018		2,018		1,330
Limited partnership interests | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		1,444		1,444		0
Limited partnership interests | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		0		0		0
Limited partnership interests | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		0		0		605
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		0	$ 1,462	605	$ 1,196
Purchases / contributions		0	281	0	419
Sales / distributions		0	0	(598)	0
Realized losses		0	0	(68)	0
Unrealized (losses) gains	[3]	0	(286)	61	(158)
Transfers into (out of) level 3		0	0	0	0
Balance at end of period		0	$ 1,457	0	$ 1,457
Company-sponsored funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments						13,376
Company-sponsored funds | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		11,486		11,486
Available-for-sale investments						14,632
Company-sponsored funds | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		11,486		11,486
Available-for-sale investments						14,632
Company-sponsored funds | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		0		0
Available-for-sale investments						0
Company-sponsored funds | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		0		0
Available-for-sale investments						0
Common stocks
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale investments						6,782
Common stocks | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		23,627		23,627		5,961
Available-for-sale investments						7,238
Common stocks | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		23,627		23,627		5,961
Available-for-sale investments						7,238
Common stocks | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		0		0		0
Available-for-sale investments						0
Common stocks | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Investments		$ 0		$ 0		0
Available-for-sale investments						$ 0
[1]	Asset and liability amounts in parentheses represent the aggregated balances at September 30, 2018 and December 31, 2017 attributable to variable interest entities consolidated by the Company. Refer to Note 4 for further discussion.
[2]	Pledged as collateral attributable to the consolidated balances of the Cohen & Steers Active Commodities Strategy Fund, Inc. at December 31, 2017.
[3]	Pertains to unrealized gains (losses) from investments still held at September 30, 2017.

Derivatives (Details)

Derivatives (Details) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Derivative [Line Items]
Derivative Assets, Notional		$ 39,739,000		$ 39,739,000		$ 8,939,000
Derivative Assets, Fair Value		1,210,000		1,210,000		487,000
Derivative Liabilities, Notional		13,004,000		13,004,000		19,155,000
Derivative Liabilities, Fair Value		596,000		596,000		350,000
Derivative, Gains (Losses) on derivative, net		228,000	$ 260,000	612,000	$ (1,930,000)
Trading investments
Derivative [Line Items]
Cash Collateral for Borrowed Securities		883,000		883,000
Trading investments and pledged as collateral	[1]	845,000		845,000		414,000
Commodity contracts
Derivative [Line Items]
Derivative Assets, Notional		21,372,000		21,372,000		8,939,000
Derivative Assets, Fair Value		469,000		469,000		487,000
Derivative Liabilities, Notional		13,004,000		13,004,000		6,876,000
Derivative Liabilities, Fair Value		596,000		596,000		286,000
Derivative, Gains (Losses) on derivative, net		(186,000)	124,000	(193,000)	(732,000)
Foreign exchange contracts
Derivative [Line Items]
Derivative Assets, Notional		18,367,000		18,367,000		0
Derivative Assets, Fair Value		741,000		741,000		0
Derivative Liabilities, Notional		0		0		12,279,000
Derivative Liabilities, Fair Value		0		0		$ 64,000
Derivative, Gains (Losses) on derivative, net		$ 414,000	$ 136,000	$ 805,000	$ (1,198,000)
[1]	Pledged as collateral attributable to the consolidated balances of the Cohen & Steers Active Commodities Strategy Fund, Inc. at December 31, 2017.

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Anti-dilutive common stock equivalents excluded from computation (in shares)	0	0		0	5,000
Net income	$ 29,731	$ 25,738	[1]	$ 84,224	$ 71,680	[1]
Less: Net (income) loss attributable to redeemable noncontrolling interest	1,059	(656)	[1]	4,111	(139)	[1]
Net income attributable to common stockholders	$ 30,790	$ 25,082	[1]	$ 88,335	$ 71,541	[1]
Basic weighted average shares outstanding (shares)	46,830,000	46,386,000	[1]	46,778,000	46,335,000	[1]
Dilutive potential shares from restricted stock units (shares)	694,000	661,000		549,000	523,000
Diluted weighted average shares outstanding (shares)	47,524,000	47,047,000	[1]	47,327,000	46,858,000	[1]
Basic earnings per share attributable to common stockholders (in dollars per share)	$ 0.66	$ 0.54	[1]	$ 1.89	$ 1.54	[1]
Diluted earnings per share attributable to common stockholders (in dollars per share)	$ 0.65	$ 0.53	[1]	$ 1.87	$ 1.53	[1]
[1]	Certain amounts have been recast to reflect the Company's adoption of the new revenue recognition accounting standard on January 1, 2018. See Notes 2 and 3 for further discussion of the Company's recently adopted accounting pronouncements and revenue, respectively.

Income Taxes (Details)

Income Taxes (Details) - USD ($)	Dec. 31, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate reconciliation, percent		25.50%	41.20%	24.40%	38.60%
Tax Cuts and Jobs Act of 2017 provisional income tax expense (benefit)	$ 8,400,000
Federal tax return overpayments		$ 680,000		$ 680,000

Regulatory Requirements (Detail

Regulatory Requirements (Details) $ in Millions	Sep. 30, 2018USD ($)
Securities Registered Domestically
Financial Instruments Owned and Pledged as Collateral [Line Items]
Net Capital	$ 3.3
Excess Capital	3.1
Securities Regulated By Hong Kong
Financial Instruments Owned and Pledged as Collateral [Line Items]
Net Capital	25.4
Excess Capital	25
Securities Regulated By UK
Financial Instruments Owned and Pledged as Collateral [Line Items]
Net Capital	33.8
Excess Capital	$ 29.1

Related Party Transactions (Det

Related Party Transactions (Details) - Affiliated Funds - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Related Party Transactions, Revenue [Abstract]
Investment advisory and administration fees	$ 62,474	$ 60,757	$ 181,368	$ 174,199
Distribution and service fees	7,451	7,808	22,108	22,867
Total	69,925	68,565	203,476	197,066
Related Party Transactions Summary [Abstract]
Proceeds from sales	3,053	0	10,782	15,105
Gross realized gains	28	0	28	80
Gross realized losses	(1)	0	(4,448)	0
Dividend income	102	141	369	529
Fund expenses, included in general and administrative expenses	2,100	$ 2,000	6,400	$ 6,200
Receivables due from company-sponsored funds	$ 23,028		$ 23,028		$ 23,666

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Loss Contingencies [Line Items]
Operating Leases, Rent Expense	$ 3	$ 3.2	$ 8.8	$ 8.8
Commitments
Loss Contingencies [Line Items]
Long-term purchase commitment, time period			12 years
Commitment to invest
Loss Contingencies [Line Items]
Long-term purchase commitment	5.1		$ 5.1
Long-term committment, funded amount	$ 3.8		$ 3.8

Concentration of Credit Risk (D

Concentration of Credit Risk (Details)	Sep. 30, 2018financial_institution
Risks and Uncertainties [Abstract]
Number of financial institutions	3

Subsequent Events (Details)

Subsequent Events (Details) - $ / shares	Nov. 07, 2018	Sep. 30, 2018	Sep. 30, 2017	[1]	Sep. 30, 2018	Sep. 30, 2017	[1]
Subsequent Event [Line Items]
Dividends declared per share (in dollars per share)		$ 0.33	$ 0.28		$ 0.99	$ 0.84
Dividend Declared | Subsequent Event
Subsequent Event [Line Items]
Dividends declared per share (in dollars per share)	$ 0.33
Common Stock, Dividends, Per Share, Cash Paid	$ 2.50
[1]	Certain amounts have been recast to reflect the Company's adoption of the new revenue recognition accounting standard on January 1, 2018. See Notes 2 and 3 for further discussion of the Company's recently adopted accounting pronouncements and revenue, respectively.