Calamos Asset Management (CLMS) 10-Q 4 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Oct. 31, 2013	Oct. 31, 2013
		Class A [Member]	Class B [Member]
Entity Information [Line Items]	'	'	'
Entity Registrant Name	'Calamos Asset Management, Inc. /DE/	'	'
Entity Central Index Key	'0001299033	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Well-known Seasoned Issuer	'No	'	'
Entity Filer Category	'Accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	20,530,571	100
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'Q3	'	'
Document Type	'10-Q	'	'
Amendment Flag	'false	'	'
Document Period End Date	30-Sep-13	'	'

CONSOLIDATED_STATEMENTS_OF_FIN

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$71,582	$106,796
Receivables:	'	'
Affiliates and affiliated funds	15,494	17,756
Customers	7,335	9,870
Investment securities	416,075	349,404
Derivative assets	0	132
Partnership investments, net	47,009	60,828
Prepaid expenses	2,971	2,240
Deferred tax assets, net	7,156	7,110
Other current assets	3,114	804
Total current assets	570,736	554,940
Non-current assets:	'	'
Deferred tax assets, net	39,670	48,198
Goodwill	6,380	6,380
Property and equipment, net of accumulated depreciation and amortization ($60,584 at September 30, 2013 and $57,190 at December 31, 2012)	16,979	19,522
Other non-current assets	2,936	3,561
Total non-current assets	65,965	77,661
Total assets	636,701	632,601
Current liabilities:	'	'
Distribution fees payable	11,076	12,937
Accrued compensation and benefits	21,878	23,953
Current portion of long-term debt	46,160	0
Interest payable	1,240	2,729
Accrued expenses and other current liabilities	6,307	5,288
Total current liabilities	86,661	44,907
Non-current liabilities:	'	'
Long-term debt	45,955	92,115
Deferred rent	9,092	9,275
Other non-current liabilities	2,987	4,455
Total non-current liabilities	58,034	105,845
Total non-current liabilities	144,695	150,752
STOCKHOLDERSb EQUITY	'	'
Additional paid-in capital	216,980	215,637
Retained earnings	77,788	77,714
Accumulated other comprehensive income (loss)	1,504	-737
Treasury stock; 4,904,350 shares at September 30, 2013 and 4,000,000 at December 31, 2012	-97,432	-95,215
Calamos Asset Management, Inc. stockholdersb equity	199,085	197,643
Total non-controlling interest	292,921	284,206
Total stockholdersb equity	492,006	481,849
Total liabilities and stockholdersb equity	636,701	632,601
Calamos Investments LLC [Member]	'	'
STOCKHOLDERSb EQUITY	'	'
Non-controlling interest in Calamos Investments LLC (Calamos Interests)	271,127	263,794
Partnership investment [Member]	'	'
STOCKHOLDERSb EQUITY	'	'
Non-controlling interest in partnership investments	21,794	20,412
Class A [Member]	'	'
STOCKHOLDERSb EQUITY	'	'
Common stock	245	244
Class B [Member]	'	'
STOCKHOLDERSb EQUITY	'	'
Common stock	$0	$0

CONSOLIDATED_STATEMENTS_OF_FIN1

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Non-current assets:	'	'
Property and equipment, accumulated depreciation	$60,584	$57,190
STOCKHOLDERSb EQUITY	'	'
Treasury stock (in shares)	4,904,350	4,000,000
Class A [Member]	'	'
STOCKHOLDERSb EQUITY	'	'
Common Stock, par value (in dollars per share)	$0.01	$0.01
Common Stock, authorized (in shares)	600,000,000	600,000,000
Common Stock, Shares issued (in shares)	24,537,707	24,386,015
Common Stock, shares outstanding (in shares)	19,633,357	20,386,015
Class B [Member]	'	'
STOCKHOLDERSb EQUITY	'	'
Common Stock, par value (in dollars per share)	$0.01	$0.01
Common Stock, authorized (in shares)	1,000	1,000
Common Stock, Shares issued (in shares)	100	100
Common Stock, shares outstanding (in shares)	100	100

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
REVENUES	'	'	'	'
Investment management fees	$51,289	$64,402	$159,886	$195,050
Distribution and underwriting fees	13,024	16,684	40,730	52,444
Other	652	761	1,992	2,305
Total revenues	64,965	81,847	202,608	249,799
EXPENSES	'	'	'	'
Employee compensation and benefits	23,508	19,781	67,453	62,926
Distribution expenses	12,913	15,957	40,085	49,992
Marketing and sales promotion	4,208	4,608	11,536	14,562
General and administrative	8,912	9,768	27,591	30,596
Total operating expenses	49,541	50,114	146,665	158,076
Operating income	15,424	31,733	55,943	91,723
NON-OPERATING INCOME	'	'	'	'
Net interest expense	-1,456	-1,396	-4,307	-4,220
Investment and other income	6,786	4,152	12,128	25,508
Total non-operating income	5,330	2,756	7,821	21,288
Income before income tax provision	20,754	34,489	63,764	113,011
Income tax provision	1,603	2,314	6,154	10,879
Net income	19,151	32,175	57,610	102,132
Net income attributable to non-controlling interest in Calamos Investments LLC (Calamos Interests)	-15,000	-26,384	-48,259	-86,974
Net income attributable to non-controlling interest in partnership investments	-1,454	-1,058	-1,579	-1,572
Net income attributable to Calamos Asset Management, Inc.	$2,697	$4,733	$7,772	$13,586
Earnings per share:	'	'	'	'
Basic (in dollars per share)	$0.14	$0.23	$0.39	$0.67
Diluted (in dollars per share)	$0.13	$0.23	$0.38	$0.66
Weighted average shares outstanding:	'	'	'	'
Basic (in shares)	19,671,742	20,373,585	19,998,922	20,316,901
Diluted (in shares)	20,387,651	20,802,592	20,599,821	20,698,105
Cash dividends per share (in dollars per share)	$0.13	$0.11	$0.38	$0.30

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other Comprehensive Income (Loss), before Tax [Abstract]	'	'	'	'
Net income	$19,151	$32,175	$57,610	$102,132
Unrealized gains on available-for-sale securities:	'	'	'	'
Changes in unrealized gains	20,094	15,115	20,485	21,469
Reclassification adjustment for (gains) losses included in net income	610	534	-4,973	-20,040
Other comprehensive income, before income tax provision	20,704	15,649	15,512	1,429
Income tax provision related to other comprehensive income	1,874	1,276	1,316	116
Other comprehensive income, after income tax provision	18,830	14,373	14,196	1,313
Comprehensive income	37,981	46,548	71,806	103,445
Comprehensive income attributable to non-controlling interest in Calamos Investments LLC (Calamos Interests)	-30,641	-38,579	-60,218	-88,094
Comprehensive income attributable to non-controlling interest in partnership investments	-1,454	-1,058	-1,579	-1,572
Comprehensive income attributable to Calamos Asset Management, Inc.	$5,886	$6,911	$10,009	$13,779

CONSOLIDATED_STATEMENT_OF_CHAN

CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Noncontrolling Interest in Calamos Investments LLC (Calamos Interests) [Member]	Noncontrolling Interest in Partnership Investments [Member]
In Thousands, unless otherwise specified
Balance at Dec. 31, 2012	$481,849	$244	$215,637	$77,714	($737)	($95,215)	$263,794	$20,412
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'	'	'	'
Net income	57,610	0	0	7,772	0	0	48,259	1,579
Changes in unrealized gains on available-for-sale securities, net of income taxes	18,761	0	0	0	2,933	0	15,828	0
Reclassification adjustment for gains on available-for-sale securities included in income, net of income taxes	-4,565	0	0	0	-696	0	-3,869	0
Issuance of common stock (151,692 Class A common shares)	0	1	-1	0	0	0	0	0
Repurchase of common stock by Calamos Investments LLC (904,350 Class A common shares)	-9,717	0	0	0	0	-2,157	-7,560	0
Impact of the redemption of common stock from Calamos Investments LLC by Calamos Asset Management, Inc. (7,136 Class A common shares)	0	0	60	0	0	-60	0	0
Cumulative impact of changes in ownership of Calamos Investments LLC	-390	0	333	-4	4	0	-723	0
Distribution to non-controlling interest in partnership investments	-197	0	0	0	0	0	0	-197
Compensation expense recognized under stock incentive plans	4,887	0	1,084	0	0	0	3,803	0
Impact on non-controlling interest as a result of dividends paid to Calamos Investments LLC on repurchased common stock	0	0	-133	0	0	0	133	0
Dividend equivalent accrued under stock incentive plans	-781	0	0	-174	0	0	-607	0
Distributions paid to non-controlling interests in Calamos Investments LLC (Calamos Interests)	-47,931	0	0	0	0	0	-47,931	0
Dividends declared	-7,520	0	0	-7,520	0	0	0	0
Balance at Sep. 30, 2013	492,006	245	216,980	77,788	1,504	-97,432	271,127	21,794
Balance at Jun. 30, 2013	'	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'	'	'	'
Net income	19,151	'	'	'	'	'	'	'
Changes in unrealized gains on available-for-sale securities, net of income taxes	18,271	'	'	'	'	'	'	'
Reclassification adjustment for gains on available-for-sale securities included in income, net of income taxes	559	'	'	'	'	'	'	'
Impact on non-controlling interest as a result of dividends paid to Calamos Investments LLC on repurchased common stock	'	'	'	'	'	'	87	'
Balance at Sep. 30, 2013	$492,006	'	'	'	'	'	$271,127	'

CONSOLIDATED_STATEMENT_OF_CHAN1

CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) (Class A [Member])	9 Months Ended
	Sep. 30, 2013
Class A [Member]	'
Issuance of common stock (in shares)	151,692
Repurchase of common stock (in shares)	904,350
Stock Issued During Period, Shares, Other	7,136

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Statement of Cash Flows [Abstract]	'	'
Cash and cash equivalents at beginning of period	$106,796	$102,166
Cash flows provided by operating activities:	'	'
Net income	57,610	102,132
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Amortization of deferred sales commissions	2,121	3,621
Other depreciation and amortization	3,441	4,199
Deferred rent	-183	-101
Change in unrealized gains on CFS securities, derivative assets, derivative liabilities and partnership investments, net	-2,306	-5,322
Net realized gain on sale of investment securities, derivative assets, derivative liabilities and partnership investments, net	-5,131	-15,917
Increase in deferred tax asset valuation allowance	900	1,900
Deferred taxes	6,170	7,124
Stock based compensation	4,887	3,300
Employee taxes paid on vesting under stock incentive plans	-294	-916
Receivables:	'	'
Affiliates and affiliated funds, net	2,262	-77
Customers	2,535	-995
Other assets	-4,579	-2,196
Decrease in liabilities:	'	'
Distribution fees payable	-1,861	-133
Accrued compensation and benefits	-2,075	-3,554
Accrued expenses and other liabilities	-2,623	-1,667
Net cash provided by operating activities	60,874	91,398
Cash flows used in investing activities:	'	'
Net additions to property and equipment	-856	-1,431
Purchase of investment securities	-374,360	-326,386
Proceeds from sale of investment securities	329,686	330,678
Net purchases of derivatives	-1,720	-12,327
Net changes in partnership investments	16,426	-1,401
Net cash paid for acquisition, net of cash acquired	0	-3,392
Net cash used in investing activities	-30,824	-14,259
Cash flows used in financing activities:	'	'
Excess tax liability on vesting under stock incentive plans	-96	-97
Repurchase of common stock by Calamos Investments LLC (904,350 Class A common shares)	-9,717	0
Distributions paid to non-controlling interest in Calamos Investments LLC (Calamos Interests)	-47,931	-55,203
Cash dividends paid to common stockholders	-7,520	-6,104
Net cash used in financing activities	-65,264	-61,404
Net increase (decrease) in cash	-35,214	15,735
Cash and cash equivalents at end of period	71,582	117,901
Cash paid for:	'	'
Income taxes, net	1,593	1,972
Interest	$5,954	$5,954

CONSOLIDATED_STATEMENTS_OF_CAS1

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) (Class A [Member])	9 Months Ended
	Sep. 30, 2013
Class A [Member]	'
Number of common stock repurchased (in shares)	904,350

Organization_and_Description_o

Organization and Description of Business	9 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Organization and Description of Business	'
	Organization and Description of Business
	Calamos Asset Management, Inc. (“CAM”) is a holding company and as of September 30, 2013 owned 22.2% of Calamos Investments LLC (“Calamos Investments”). CAM, together with Calamos Investments and Calamos Investments’ subsidiaries (the “Company”), operates the investment advisory and distribution services businesses reported within these consolidated financial statements. CAM operates and controls all of the business and affairs of Calamos Investments and, as a result of this control, consolidates the financial results of Calamos Investments with its own financial results. The remaining 77.8% ownership interest in Calamos Investments is held by Calamos Family Partners, Inc. (“CFP”), a Delaware corporation, and John P. Calamos, Sr. the Chairman, Chief Executive Officer and Global Co-Chief Investment Officer of CAM. CFP and John P. Calamos, Sr. (collectively "Calamos Interests"), ownership interest, in accordance with applicable accounting guidance, is reflected and referred to within these consolidated financial statements as “non-controlling interest in Calamos Investments LLC”. As shown in the diagram below, CFP also owns all of CAM’s outstanding Class B common stock, which represents 97.4% of the combined voting power of all classes of CAM’s voting stock. The graphic below illustrates our organizational and ownership structure as of September 30, 2013:
	______
	-1	Represents combined economic interest of Calamos Family Partners, Inc. and John P. Calamos, Sr. who is also a member of Calamos Investments LLC.
	-2	Represents combined economic interest of all public stockholders, including John P. Calamos, Sr., Nick Calamos and John P. Calamos, Jr.’s combined 11.88% ownership interest of Class A common stock. The calculation of ownership interest includes options and RSUs that vest within 60 days, as well as CFP’s ownership interest in Class A common stock purchased by Calamos Investments, pursuant to the Company’s share repurchase plan.
	The Company primarily provides investment advisory services to individuals and institutional investors through a number of investment products that include open-end funds and closed-end funds (the “Funds”), separate accounts, offshore funds and partnerships, as well as provides model portfolio design and oversight for separately managed accounts. The subsidiaries through which the Company provides these services include: Calamos Advisors LLC (“CAL”), a Delaware limited liability company and registered investment advisor; Calamos Financial Services LLC (“CFS”), a Delaware limited liability company and registered broker-dealer; Calamos Wealth Management LLC, a Delaware limited liability company and registered investment advisor; and Calamos Investments LLP, a United Kingdom limited liability partnership, registered investment advisor with the Financial Conduct Authority in the United Kingdom, and a global distributor of the offshore funds and Company products. For reporting purposes, the offshore funds are reported within the open-end funds.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	Summary of Significant Accounting Policies
	Basis of Presentation
	The consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”), which require the use of estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities. Management believes the accounting estimates are appropriate and reasonably stated; however, due to the inherent uncertainties in making estimates, actual amounts could differ from these estimates.
	The consolidated financial statements as of September 30, 2013 and for the three and nine months ended September 30, 2013 and 2012 have not been audited by the Company’s independent registered public accounting firm. In the opinion of management, these statements contain all adjustments, including those of a normal recurring nature, necessary for fair presentation of the financial condition and results of operations. The results for the interim periods presented are not necessarily indicative of the results to be obtained for a full fiscal year. This Form 10-Q filing should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2012.
	The Company consolidates investments in which the Company’s ownership exceeds 50% or in which the Company operates and controls the business and affairs of the entity. As such, the consolidated financial statements include the financial statements of CAM, Calamos Investments and Calamos Investments’ wholly- and majority-owned subsidiaries, and the Company’s partnerships in which it owns a majority interest or in which it has operating control. The equity method of accounting is used for investments in which the Company has significant influence, but less than 50% ownership. All significant intercompany balances and transactions have been eliminated.
	The Calamos Interests’ combined 77.8% and 77.9% ownership interest in Calamos Investments as of September 30, 2013 and December 31, 2012, respectively, is represented as a non-controlling interest in Calamos Investments LLC in the Company’s consolidated financial statements. Non-controlling interest in Calamos Investments is derived by multiplying the historical equity of Calamos Investments by the Calamos Interests’ aggregate ownership percentage for the periods presented. Issuances and repurchases of CAM’s common stock may result in changes in CAM’s ownership percentage and to the non-controlling interests’ ownership percentage of Calamos Investments with resulting changes reflected in the consolidated statement of changes in stockholders’ equity. Income is allocated based on the average ownership interest during the period in which the income is earned.
	CAL is the general partner and controls the operations of Calamos International Growth Fund LP. Calamos Investments, through a wholly-owned subsidiary, indirectly is the general partner and controls the operations of Calamos Arista Strategic Fund LP, a U.S. feeder fund to Calamos Arista Strategic Master Fund LTD, a hedge fund domiciled in the Cayman Islands. As CAL and Calamos Investments are the general partners and control the operations of these funds, and Calamos Investments has a majority interest in Calamos Arista Strategic Fund LP, the results of Calamos International Growth Fund LP, Calamos Arista Strategic Fund LP and Calamos Arista Strategic Master Fund LTD are included in the Company’s consolidated financial results.
	For the periods the partnerships are consolidated, the assets and liabilities of the partnerships are presented on a net basis within partnership investments, net in the consolidated statements of financial condition, net income is included in investment and other income in the consolidated statements of operations, and the change in partnership investments is included in the net changes in partnership investments in the consolidated statements of cash flows. The partnerships are presented on a net basis in order to provide more clarity to the financial position and results of the core operations of the Company. The underlying assets and liabilities that are being consolidated are described in Note 5, Partnership Investments. The combined interests of all of the consolidated partnerships, not owned by the Company, are presented as non-controlling interest in partnership investments in the Company’s consolidated financial statements for the periods those partnerships were consolidated.
	The Company holds non-controlling interests in certain other partnership investments that are included in partnership investments, net in the consolidated statements of financial condition. These other partnership investments are accounted for under the equity method.
	Reclassifications
	During the first quarter ended March 31, 2013, the Company changed the presentation of its consolidated statements of operations and consolidated statements of financial condition. The changes consisted of the classification of amortization of deferred sales commissions, previously presented as a separate line, now included with distribution expenses; and the classification of deferred sales commissions asset, previously presented on a separate line, now included with other non-current assets. Deferred sales commissions asset and amortization became immaterial, with the discontinuation of the sale of Class B shares, making the separate line presentations less meaningful to the financial statement users.
	Certain investments previously presented as Other are being presented as Alternative in Note 3, Investment Securities, and Note 6, Fair Value Measurements.
	These reclassifications have been made for all periods presented.
	Restricted Cash
	The Company has $430,000 of security deposits that are restricted from the Company’s general corporate use and are being reported in other non-current assets in the consolidated statements of financial condition.
	Treasury Stock
	During the first quarter of 2013, the Company’s board of directors approved a Class A common share repurchase program. Under the repurchase program, Calamos Investments is authorized to repurchase up to 3 million shares of CAM’s common stock. The share repurchases are expected to occur over the next 2 years. The program was implemented primarily to manage the dilution from share issuances under the Company’s incentive compensation plan. During the nine months ended September 30, 2013, Calamos Investments repurchased 904,350 Class A common stock, at an average purchase price of $10.74 and a total cost of $9.7 million. As Calamos Investments is consolidated with CAM, the repurchased shares are reported as treasury shares.  As such, CAM’s 22.2% ownership interest in these shares totaling $2.2 million is reported in treasury stock, with Calamos Interests’ 77.8% ownership interest in these shares totaling $7.6 million reported in non-controlling interest in the consolidated statements of financial condition. The total shares repurchased are not included in the calculation of basic and diluted earnings per share in accordance with GAAP.
	During the third quarter of 2013, CAM redeemed 7,136 Class A common shares from Calamos Investments for a value of $77,000 which represents the fair value of the shares on the date of redemption. As Calamos Investments is consolidated with CAM, the impact of the distribution reflecting the non-controlling interest is $60,000.
	During the third quarter and nine months ended September 30, 2013, dividends on shares held by Calamos Investments totaled $112,000 and $171,000, respectively. The payment of these dividends increased Calamos Investments' equity resulting in a $87,000 adjustment for the third quarter, and a $133,000 adjustment for the nine months ended September 30, 2013 from additional paid in capital to non-controlling interest in Calamos Investments LLC, in the consolidated statement of changes in stockholders' equity. This adjustment represents Calamos Interests' ownership interest in those dividend payments.
	Investment Securities
	Investment securities that are available-for-sale are evaluated for other-than-temporary impairment on a quarterly basis when the cost of an investment exceeds its fair value. When evaluating these securities, we consider many factors, including the duration of the impairment, the severity of the impairment, subsequent changes in value, the Company's intent and ability to hold these securities for a period of time sufficient to allow for recovery of the market value, and the nature of the securities held. When an impairment of an equity security is determined to be other-than-temporary, the impairment is recognized in earnings. See Note 3, Investment Securities for more discussion related to the other-than-temporary impairment charge recorded in the second quarter of 2013.
	Income Taxes
	Deferred tax assets and liabilities are recognized for the future tax consequences attributable to the temporary differences between the financial statement carrying amount of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. During the second quarter ended June 30, 2013, the Company recorded a valuation allowance to reduce its deferred income tax assets to an amount that is more likely than not to be realized based on available evidence at the time the estimate was made. No additional adjustment to the valuation allowances was made in the third quarter ended September 30, 2013. Determining a valuation allowance requires management to make significant judgments and assumptions. In determining a valuation allowance the Company uses historical and forecasted future realized and unrealized gains and losses on its investment, ongoing tax planning strategies, and forecasts of future taxable income. Each quarter, the Company re-evaluates its estimates related to its valuation allowance, including its assumptions about future taxable income. Applying its tax harvesting strategies, the Company's capital loss carryforward is used against realized gains on its investment, derivative assets, derivative liabilities and partnership investments. See Note 10, Income Taxes for more discussion related to the deferred tax valuation allowance.
	For a comprehensive disclosure of the Company's significant accounting policies, see the Company's Annual Report on Form 10-K for the year ended December 31, 2012.

Investment_Securities

Investment Securities	9 Months Ended
	Sep. 30, 2013
Investments [Abstract]	'
Investment Securities	'
	Investment Securities
	As a registered broker-dealer, CFS is required to carry all investment securities it owns at fair value and record all changes in fair value in current earnings. As such, unrealized gains and losses on CFS securities, as well as realized gains and losses on all investment securities, are included in investment and other income in the consolidated statements of operations. The following tables provide a summary of investment securities owned by the Company as of September 30, 2013 and December 31, 2012:
		September 30, 2013
	(in thousands)
					Unrealized			Unrealized
		Cost			Gains			Losses			Fair Value
	Available-for-sale securities:
	Funds
	Equity	$	212,069		$	12,257		$	(1	)	$	224,325
	Fixed income	105,443			291			(2,844		)	102,890
	Lower-volatility equity	45,501			1,950			—			47,451
	Alternative	35,269			192			—			35,461
	Other	1,385			65			(10		)	1,440
	Total Funds	399,667			14,755			(2,855		)	411,567
	Common stock	132			39			—			171
	Total available-for-sale securities	$	399,799		$	14,794		$	(2,855	)	$	411,738
	CFS securities:
	Total CFS securities	$	3,913		$	424		$	—		$	4,337
	Total investment securities										$	416,075
		December 31, 2012
	(in thousands)
					Unrealized			Unrealized
		Cost			Gains			Losses			Fair Value
	Available-for-sale securities:
	Funds
	Equity	$	195,553		$	2,930		$	(5,517	)	$	192,966
	Fixed income	103,404			665			(957		)	103,112
	Lower-volatility equity	43,718			106			(484		)	43,340
	Alternative	5,058			2			(92		)	4,968
	Other	1,543			42			(270		)	1,315
	Total Funds	349,276			3,745			(7,320		)	345,701
	Common stock	131			1			—			132
	Total available-for-sale securities	$	349,407		$	3,746		$	(7,320	)	$	345,833
	CFS securities:
	Total CFS securities	$	3,004		$	567		$	—		$	3,571
	Total investment securities										$	349,404
	Of the $415.9 million and $349.3 million investments in Funds at September 30, 2013 and December 31, 2012, respectively, $364.6 million and $295.0 million, respectively, were invested in affiliated funds.
	The aggregate fair value of available-for-sale investment securities that were in an unrealized loss position at September 30, 2013 and December 31, 2012 was $79.8 million and $251.3 million, respectively, of which at September 30, 2013 and December 31, 2012 investment securities with a fair value of $0 and $123.9 million, respectively, were in a continuous loss position for 12 months or longer.
	The Company recognized an other-than-temporary impairment charge of $4.4 million, recorded on certain available-for-sale securities with unrealized losses during the second quarter ended June 30, 2013. The other-than-temporary impairment charge was reported in non-operating income, in the consolidated statements of operations. As of September 30, 2013, the Company had no investment securities that had been in a continuous loss position for 12 months or longer.
	The table below summarizes information on available-for-sale securities as well as the change in unrealized gains and losses on CFS securities for the three and nine months ended September 30, 2013 and 2012:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2013			2012			2013			2012
	(in thousands)
	Available-for-sale securities:
	Proceeds from sale	$	77,465		$	54,162		$	325,447		$	330,678
	Gross realized gains on sales	$	2,833		$	1,833		$	10,171		$	28,273
	CFS securities:
	Change in unrealized gains (losses)	$	429		$	153		$	(143	)	$	318
	The tables below summarize the tax (provision) benefit on unrealized gains and gains reclassified out of accumulated other comprehensive income on available-for-sale securities for the three and nine months ended September 30, 2013 and 2012:
		Three Months Ended									Three Months Ended
		September 30, 2013									September 30, 2012
	(in thousands)	Before-Tax Amount			Tax Provision			After-Tax			Before-Tax Amount			Tax Provision			After-Tax
								Amount									Amount
	Available-for-sale securities:
	Changes in unrealized gains	$	20,094		$	(1,823	)	$	18,271		$	15,115		$	(1,234	)	$	13,881
	Reclassification adjustment for realized losses included in income	610			(51		)	559			534			(42		)	492
	Other comprehensive income	$	20,704		$	(1,874	)	$	18,830		$	15,649		$	(1,276	)	$	14,373
		Nine Months Ended									Nine Months Ended
		September 30, 2013									September 30, 2012
	(in thousands)	Before-Tax Amount			Tax (Provision) Benefit			After-Tax			Before-Tax Amount			Tax (Provision) Benefit			After-Tax
								Amount									Amount
	Available-for-sale securities:
	Changes in unrealized gains	$	20,485		$	(1,724	)	$	18,761		$	21,469		$	(1,753	)	$	19,716
Reclassification adjustment for realized gains included in income	(4,973		)	408			(4,565		)	(20,040		)	1,637			(18,403		)
Other comprehensive income	$	15,512		$	(1,316	)	$	14,196		$	1,429		$	(116	)	$	1,313
Reclassification of realized (gains) losses out of accumulated other comprehensive income are reported in non-operating income, in investment income, in the consolidated statements of operations.  See Note 9, Non-operating Income.

Derivative_Assets_and_Liabilit

Derivative Assets and Liabilities	9 Months Ended
	Sep. 30, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Assets and Liabilities	'
	Derivative Assets and Liabilities
	The Company has used exchange traded option contracts as an economic hedge of price changes in its investment securities portfolio in order to reduce the volatility equity markets have on the fair value of the Company’s corporate investment portfolio and to assist in compliance with its debt covenants. The Company's investment securities totaling $416.1 million at September 30, 2013, consist primarily of positions in several Calamos equity funds and fixed income funds. The equity price risk in the investment portfolio has been hedged using exchange-traded option contracts that correlate most closely with the change in value of the portfolio being hedged. The use of these option contracts is part of a hedge overlay strategy to minimize downside risk in the hedged portfolio. The Company may adjust its hedge position in response to movement and volatility in prices and changes in the composition of the hedged portfolio, but generally is not actively buying and selling contracts.
	When applicable, the fair value of option contracts is reported in derivative assets and derivative liabilities in the consolidated statements of financial condition. Net gains and losses on these contracts are reported in investment and other income in the consolidated statements of operations with net losses of $0 and $108,000 for the quarter ended September 30, 2013 and 2012, respectively. Net losses of $1.9 million and $8.2 million were recorded for the nine months ended September 30, 2013 and 2012, respectively. The Company has used these derivatives for risk management purposes but has not designated the contracts as hedges for accounting purposes.
	The Company adopted a recent accounting pronouncement that requires certain disclosures if offsetting arrangements exist with the Company’s derivatives instruments. The Company had no derivative instruments outstanding as of September 30, 2013.

Partnership_Investments

Partnership Investments	9 Months Ended
	Sep. 30, 2013
Partnership Investments [Abstract]	'
Partnership Investments	'
	Partnership Investments
	Presented below are the underlying assets and liabilities of the partnerships that the Company reports on a net consolidated basis, as well as partnership investments that the Company accounts for under the equity method. These investments are presented collectively as partnership investments, net in the consolidated statements of financial condition as of September 30, 2013 and December 31, 2012.
	(in thousands)	September 30, 2013			December 31, 2012
	Consolidated partnership:
	Securities owned	$	35,118		$	30,910
	Cash and cash equivalents	16,698			12,720
	Receivables for securities sold	269			—
	Other current assets	324			743
	Exchange-traded option contracts	85			13
	Securities sold not yet purchased	(7,817		)	(5,746		)
	Payables for securities purchased	(997		)	—
	Accrued expenses and other current liabilities	(308		)	(739		)
	Total	43,372			37,901
	Equity method investment in partnerships	3,637			22,927
	Partnership investments, net	$	47,009		$	60,828
	During the first quarter ended March 31, 2013, the Company redeemed $18.7 million of its interest in Calamos Global Opportunity Fund LP for proceeds of $20.0 million, resulting in a realized gain of $1.3 million.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	Fair Value Measurements
	The Company utilizes a three-tier fair value hierarchy which prioritizes the inputs used in measuring fair value as follows: Level 1 — observable inputs such as quoted prices for identical assets and liabilities in active markets; Level 2 — inputs, other than the quoted prices in active markets, that are observable either directly or indirectly (including quoted prices of similar securities, interest rates, credit risk, fair value adjustments to quoted foreign securities, etc.); and Level 3 — unobservable inputs in which there is little or no market data, and require the reporting entity to develop its own assumptions. For each period presented, the Company did not have any assets or liabilities measured at fair value using Level 3 measurements. Transfers between levels are measured at the end of the reporting period. The Company had no transfers between levels during the reporting periods.
	Investments are presented in the consolidated financial statements at fair value in accordance with GAAP. Investments in open-end funds are stated at fair value based on end of day published net asset values of shares owned by the Company. Investments in securities traded on a national securities exchange are stated at the last reported sales price on the day of valuation. Other securities, including derivatives, traded in the over-the-counter market and listed securities for which no sale was reported on that date are stated at the last quoted bid price. However, short sales positions and call options written are reported at the last quoted asked price. Fixed income securities, including convertible bonds and other securities for which quotations are not readily available are valued at fair value based on observable inputs such as market prices for similar instruments as validated by third-party pricing agencies and the Company’s prime broker.
	The following tables provide the hierarchy of inputs used to derive the fair value of the Company’s assets and liabilities measured at fair value on a recurring basis as of September 30, 2013 and December 31, 2012, respectively. Foreign currency contracts are carried in our partnership investments and are presented on a net basis where the right of offset exists. There were no material foreign currency contracts for either period presented.
					Fair Value Measurements Using
		September 30, 2013			Quoted Prices
					in Active			Significant
	(in thousands)				Markets for			Other
	Description				Identical Assets			Observable
					and Liabilities			Inputs
					(Level 1)			(Level 2)
	Cash and cash equivalents
	Money market funds	$	3,810		$	3,810		$	—
	Investment securities (Note 3)
	Funds
	Equity	228,664			228,664			—
	Fixed income	102,890			102,890			—
	Lower-volatility equity	47,451			47,451			—
	Alternative	35,461			35,461			—
	Other	1,440			1,440			—
	Total Funds	415,906			415,906			—
	Common stock	171			171			—
	Investment securities	416,077			416,077			—
	Derivative assets (Note 4)
	Exchange-traded put option contracts	—			—			—
	Securities and derivatives owned by partnership (Note 5)
	Common stocks	34,789			23,988			10,801
	Preferred stocks	151			—			151
	Short term investments	270			—			270
	Exchange-traded put option contracts	315			315			—
		35,525			24,303			11,222
	Securities sold but not yet purchased by partnership (Note 5)
	Common stocks	(7,796		)	(7,796		)	—
	Exchange-traded call option contracts	(74		)	(74		)	—
	Forward foreign currency contracts	—			—			—
	Securities sold but not yet purchased (Note 3)
	Common stocks	(2		)	(2		)	—
		(7,872		)	(7,872		)	—
	Total	$	447,540		$	436,318		$	11,222
					Fair Value Measurements Using
		December 31, 2012			Quoted Prices
	(in thousands)				in Active			Significant
	Description				Markets for			Other
					Identical Assets			Observable
					and Liabilities			Inputs
					(Level 1)			(Level 2)
	Cash and cash equivalents
	Money market funds	$	2,700		$	2,700		$	—
	Investment securities (Note 3)
	Funds
	Equity	196,537			196,537			—
	Fixed income	103,112			103,112			—
	Lower-volatility equity	43,340			43,340			—
	Alternative	6,062			6,062			—
	Other	1,315			1,315			—
	Total Funds	350,366			350,366			—
	Common stock	132			132			—
	Investment securities	350,498			350,498			—
	Derivative assets (Note 4)
	Exchange-traded put option contracts	132			132			—
	Securities and derivatives owned by partnership (Note 5)
	Common stocks	29,742			20,105			9,637
	Preferred stocks	1,167			1,167			—
Short term investments	467			—			467
Exchange-traded put option contracts	75			75			—
Forward foreign currency contracts	45			45			—
	31,496			21,392			10,104
Securities sold but not yet purchased by partnership (Note 5)
Common stocks
Common stocks	(5,746		)	(5,746		)	—
Exchange-traded call option contracts	(62		)	(62		)	—
Forward foreign currency contracts	(45		)	(45		)	—
Securities sold but not yet purchased (Note 3)
Common stocks	(1,094		)	(1,094		)	—
	(6,947		)	(6,947		)	—
Total	$	377,879		$	367,775		$	10,104
The fair value of the Company’s long-term debt, which has a total carrying value of $92.1 million at September 30, 2013 and December 31, 2012, was $104.4 million and $110.1 million, respectively. The fair value of the Company’s payment obligation, which has a carrying value of $3.4 million at September 30, 2013 and December 31, 2012, was $3.3 million and $3.2 million, respectively. This obligation is associated with the Company's purchase of Black Capital, LLC in 2012, with the current portion reported in accrued expenses and other current liabilities and the non-current portion reported in other non-current liabilities in the consolidated statements of financial condition. These fair value estimates are calculated using discounted cash flows based on the Company’s incremental borrowing rates and market inputs for similar bonds for the debt, and the treasury yield curve plus market spread for the payment obligation. The fair value of the debt and payment obligation are based on Level 2 inputs within the fair value hierarchy.
The carrying value of all other financial instruments approximates fair value due to the short maturities of these financial instruments.

Loans_Payable

Loans Payable	9 Months Ended
	Sep. 30, 2013
Loans Payable [Abstract]	'
Loans Payable	'
	Loans Payable
	The Company has access to margin loans for the settlement of call options, as well as an additional source of liquidity. The interest rates that can be charged on margin loans is 2.50% per annum, based on the brokerage firm’s lending rate. These loans are due on demand. The Company can borrow up to 70% of its marginable securities on deposit with its brokerage firm. The Company had no margin loan balances outstanding at September 30, 2013 and December 31, 2012.

Stock_Based_Compensation

Stock Based Compensation	9 Months Ended
	Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock Based Compensation	'
	Stock Based Compensation
	Under the Company’s incentive compensation plan, certain employees of the Company receive stock based compensation comprised of stock options and restricted stock units (“RSUs”). Historically, RSUs have been settled with newly issued shares so that no cash was used by the Company to settle awards; however, the Company may also use treasury shares upon the exercise of stock options and upon conversion of RSUs. The Company’s Annual Report on Form 10-K for the year ended December 31, 2012 provides details of this plan and its provisions.
	During the nine months ended September 30, 2013, the Company granted 838,663 RSUs and there were 403,873 RSUs forfeited. During the same period, the Company granted no stock options and there were 93,846 stock options forfeited.
	During the nine months ended September 30, 2013, 178,903 RSUs vested with 27,211 units withheld for taxes and 151,692 RSUs converted into an equal number of shares of CAM’s Class A common stock. The total intrinsic value and the fair value of the converted shares was $1.7 million. The total tax benefit realized in connection with the vesting of the RSUs during the nine months ended September 30, 2013 was $184,000, as the Company receives tax benefits based upon the portion of Calamos Investments’ expense that it recognizes.
	During the nine months ended September 30, 2013 and 2012, compensation expense recorded in connection with the RSUs and stock options was $4.9 million and $3.3 million, respectively, of which $1,084,000 and $726,000, respectively, was credited as additional paid-in capital after giving effect to the non-controlling interests. The amount of deferred tax asset created was $401,000 and $269,000 during the nine months ended September 30, 2013 and 2012, respectively. As of September 30, 2013, $19.6 million of total unrecognized compensation expense related to unvested stock option and RSU awards is expected to be recognized over a weighted-average period of 3.4 years.

NonOperating_Income

Non-Operating Income	9 Months Ended
	Sep. 30, 2013
Other Income and Expenses [Abstract]	'
Non-Operating Income (Loss)	'
	Non-operating Income
	Non-operating income was comprised of the following components for the three and nine months ended September 30, 2013 and 2012:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
	(in thousands)
	Interest income	$	49		$	107		$	209		$	291
	Interest expense	(1,505		)	(1,503		)	(4,516		)	(4,511		)
	Net interest expense	(1,456		)	(1,396		)	(4,307		)	(4,220		)
	Investment income	5,603			3,187			9,086			22,811
	Dividend income	1,020			877			2,755			2,453
	Miscellaneous other income	163			88			287			244
	Investment and other income	6,786			4,152			12,128			25,508
	Non-operating income	$	5,330		$	2,756		$	7,821		$	21,288

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	Calamos Investments is subject to certain income-based state taxes; therefore, income taxes reflect not only the portion attributed to CAM stockholders but also a portion of income taxes attributable to non-controlling interests.
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
	(in thousands)
	Income tax provision	$	1,603		$	2,314		$	6,154		$	10,879
	Income tax (provision) benefit attributable to non-controlling interest in Calamos Investments	10			377			(37		)	183
	Income tax provision attributable to CAM	1,613			2,691			6,117			11,062
	Net income attributable to CAM	2,697			4,733			7,772			13,586
	Income before taxes attributable to CAM	$	4,310		$	7,424		$	13,889		$	24,648
	CAM’s effective income tax rate	37.4		%	36.2		%	44		%	44.9		%
	As of December 31, 2012, the Company’s total capital loss carryforward was $28.1 million, of which $21.8 million will expire in 2013, $5.8 million will expire in 2014, and $456,000 will expire in 2017, if not used before the expiration dates. As of September 30, 2013, the Company’s valuation allowance on this deferred tax asset was $8.0 million.
	The effective tax rates for the first nine months of 2013 and 2012, include the impact of an increase in the deferred tax valuation allowance of $900,000 and $1.9 million, respectively, to reduce our deferred income tax assets to an amount that is more likely than not to be realized. Excluding the deferred tax valuation allowance, our effective income tax rates would be 37.6% and 37.2% for the first nine months ended September 30, 2013 and September 30, 2012, respectively.

Earnings_Per_Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	Earnings Per Share
	The following table reflects the calculation of basic and diluted earnings per share:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(in thousands, except per share data)	2013			2012			2013		2012
	Earnings per share – basic
	Earnings available to common shareholders	$	2,697		$	4,733		$	7,772	$	13,586
	Weighted average shares outstanding	19,672			20,374			19,999		20,317
	Earnings per share – basic	$	0.14		$	0.23		$	0.39	$	0.67
	Earnings per share – diluted
	Earnings available to common shareholders	$	2,697		$	4,733		$	7,772	$	13,586
	Weighted average shares outstanding	19,672			20,374			19,999		20,317
	Dilutive impact of restricted stock units	716			429			601		381
	Weighted average diluted shares outstanding	20,388			20,803			20,600		20,698
	Earnings per share – diluted	$	0.13		$	0.23		$	0.38	$	0.66
	When dilutive, diluted shares outstanding are calculated (a) assuming that Calamos Interests exchanged all of their ownership interest in Calamos Investments and their CAM Class B common stock for shares of CAM’s Class A common stock (the "Exchange") and (b) including the effect of outstanding dilutive equity incentive compensation awards. As of September 30, 2013 and 2012, the impact of the Exchange was anti-dilutive and, therefore, excluded from the calculation of diluted earnings per share.
	The Company uses the treasury stock method to reflect the dilutive effect of unvested RSUs and unexercised stock options on diluted earnings per share. Under the treasury stock method, if the average market price of common stock increases above the option’s exercise price, the proceeds that would be assumed to be realized from the exercise of the option would be used to acquire outstanding shares of common stock. However, the awards may be anti-dilutive even when the market price of the underlying stock exceeds the option’s exercise price. This result is possible because compensation cost attributed to future services and not yet recognized is included as a component of the assumed proceeds upon exercise. The dilutive effect of such options and RSUs would increase the weighted average number of shares used in the calculation of diluted earnings per share.
	The Company amended its certificate of incorporation requiring that the Exchange be based on a fair value approach (details of the amendment are set forth in the Company’s Schedule 14C filed with the Securities and Exchange Commission on January 12, 2009). The amendment results in the same or fewer shares of Class A common stock being issued at the time of the Exchange.
	The shares issued upon Exchange as presented are estimated solely on the formula as described in the Schedule 14C that does not necessarily reflect all inputs used in a fair valuation. It is critical to note that this formula does not incorporate certain economic factors and as such, in the event of an actual Exchange, the majority of the Company’s independent directors may determine the fair market value of CAM’s net assets and its ownership in Calamos Investments. For example, premiums and/or discounts for control and marketability as well as a different discount rate for future cash flows may be applied. Therefore, the directors’ valuation may result in the actual number of shares being materially different from the shares presented. Further, based upon currently available information, the Company believes it is extremely remote that any Exchange would transpire without a fair market valuation of CAM’s net assets and an agreement by Calamos Interests to Exchange, based upon that fair market valuation.
	The following table shows the number of shares which were excluded from the computation of diluted earnings per share as they were anti-dilutive:
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2013		2012			2013		2012
	Exchange of Calamos Interests’ ownership in Calamos Investments for shares of Class A common stock	31,877,237		41,710,042			31,877,237		41,710,042
	Restricted stock units	—		6,934			—		—
	Stock options	2,101,568		2,196,591			2,101,568		2,196,591
	Total	33,978,805		43,913,567			33,978,805		43,906,633
	The maximum number of shares of Class A common stock that could be issued to the Calamos Interests upon exchange is 68,784,032 as of September 30, 2013.

Recently_Issued_Accounting_Pro

Recently Issued Accounting Pronouncements	9 Months Ended
	Sep. 30, 2013
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]	'
Recently Issued Accounting Pronouncements	'
	Recently Issued Accounting Pronouncements
	The Company has reviewed all newly issued accounting pronouncements that are applicable to its business and to the preparation of its consolidated financial statements, including those not yet required to be adopted. The Company does not believe any such pronouncements will have a material effect on the Company’s financial position or results of operations. Accounting guidance that either have become effective this year or will become effective in future years, with respect to the Company’s consolidated financial statements, are described below:
	In July 2013, the Financial Accounting Standards Board (FASB) issued new guidance on the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, similar tax loss, or tax credit carryforward exists. This guidance is intended to reduce the diversity in presentation of unrecognized tax benefits. This guidance is effective for annual and interim periods beginning on or after December 15, 2013. The Company’s effective date is January 1, 2014. The Company’s current disclosures conform to this guidance and adopting this guidance does not add to the current disclosure requirements nor impact on the Company’s financial position or results of operations.
	In July 2013, the FASB issued new guidance that permits the Fed Funds Effective Swap Rate to be used as a benchmark interest rate for hedge accounting purposes in addition to interest rates on direct United States Treasury obligations and the LIBOR. This guidance is effective for qualifying new or redesigned hedging relationships entered into on or after July 17, 2013. At September 30, 2013, the Company had no hedging relationships in place. The adoption of this guidance had no impact on the Company’s financial position or results of operations.
	In February 2013, the FASB issued new guidance that requires an entity to provide additional information about reclassifications out of accumulated other comprehensive income. The amendments in this update supersede and replace the presentation requirements for reclassifications out of accumulated other comprehensive income in previously amended updates. This guidance is effective prospectively for annual and interim periods beginning on or after December 15, 2012. The Company’s effective date is January 1, 2013. The Company has adopted this guidance, which required the Company to disclose the impact of realized gains on net income that were previously reported in accumulated other comprehensive income and were reclassified out. As this pronouncement is disclosure related, the adoption of this guidance had no impact on the Company’s financial position or results of operations.
	In December 2011, the FASB issued new guidance that requires an entity to disclose information about offsetting and related arrangements to enable users of its financial statements to understand the effect of those arrangements on its financial position. This guidance is effective for annual and interim periods beginning on or after January 1, 2013. An entity should provide the disclosures required by those amendments retrospectively for all comparative periods presented. This guidance became effective and was adopted by the Company during the first quarter of this year. The adoption of this guidance currently has no effect on the Company’s financial position or disclosure. However, when applicable, this guidance will result in additional disclosures related to the Company’s derivative instruments that have offsetting arrangements.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Principles of Consolidation	'
	The Company consolidates investments in which the Company’s ownership exceeds 50% or in which the Company operates and controls the business and affairs of the entity. As such, the consolidated financial statements include the financial statements of CAM, Calamos Investments and Calamos Investments’ wholly- and majority-owned subsidiaries, and the Company’s partnerships in which it owns a majority interest or in which it has operating control. The equity method of accounting is used for investments in which the Company has significant influence, but less than 50% ownership. All significant intercompany balances and transactions have been eliminated.
	The Calamos Interests’ combined 77.8% and 77.9% ownership interest in Calamos Investments as of September 30, 2013 and December 31, 2012, respectively, is represented as a non-controlling interest in Calamos Investments LLC in the Company’s consolidated financial statements. Non-controlling interest in Calamos Investments is derived by multiplying the historical equity of Calamos Investments by the Calamos Interests’ aggregate ownership percentage for the periods presented. Issuances and repurchases of CAM’s common stock may result in changes in CAM’s ownership percentage and to the non-controlling interests’ ownership percentage of Calamos Investments with resulting changes reflected in the consolidated statement of changes in stockholders’ equity. Income is allocated based on the average ownership interest during the period in which the income is earned.
	CAL is the general partner and controls the operations of Calamos International Growth Fund LP. Calamos Investments, through a wholly-owned subsidiary, indirectly is the general partner and controls the operations of Calamos Arista Strategic Fund LP, a U.S. feeder fund to Calamos Arista Strategic Master Fund LTD, a hedge fund domiciled in the Cayman Islands. As CAL and Calamos Investments are the general partners and control the operations of these funds, and Calamos Investments has a majority interest in Calamos Arista Strategic Fund LP, the results of Calamos International Growth Fund LP, Calamos Arista Strategic Fund LP and Calamos Arista Strategic Master Fund LTD are included in the Company’s consolidated financial results.
	For the periods the partnerships are consolidated, the assets and liabilities of the partnerships are presented on a net basis within partnership investments, net in the consolidated statements of financial condition, net income is included in investment and other income in the consolidated statements of operations, and the change in partnership investments is included in the net changes in partnership investments in the consolidated statements of cash flows. The partnerships are presented on a net basis in order to provide more clarity to the financial position and results of the core operations of the Company. The underlying assets and liabilities that are being consolidated are described in Note 5, Partnership Investments. The combined interests of all of the consolidated partnerships, not owned by the Company, are presented as non-controlling interest in partnership investments in the Company’s consolidated financial statements for the periods those partnerships were consolidated.
	The Company holds non-controlling interests in certain other partnership investments that are included in partnership investments, net in the consolidated statements of financial condition. These other partnership investments are accounted for under the equity method.
Reclassifications	'
	Reclassifications
	During the first quarter ended March 31, 2013, the Company changed the presentation of its consolidated statements of operations and consolidated statements of financial condition. The changes consisted of the classification of amortization of deferred sales commissions, previously presented as a separate line, now included with distribution expenses; and the classification of deferred sales commissions asset, previously presented on a separate line, now included with other non-current assets. Deferred sales commissions asset and amortization became immaterial, with the discontinuation of the sale of Class B shares, making the separate line presentations less meaningful to the financial statement users.
	Certain investments previously presented as Other are being presented as Alternative in Note 3, Investment Securities, and Note 6, Fair Value Measurements.
	These reclassifications have been made for all periods presented.
Restricted Cash	'
	Restricted Cash
	The Company has $430,000 of security deposits that are restricted from the Company’s general corporate use and are being reported in other non-current assets in the consolidated statements of financial condition.
Treasury Stock	'
	Treasury Stock
	During the first quarter of 2013, the Company’s board of directors approved a Class A common share repurchase program. Under the repurchase program, Calamos Investments is authorized to repurchase up to 3 million shares of CAM’s common stock. The share repurchases are expected to occur over the next 2 years. The program was implemented primarily to manage the dilution from share issuances under the Company’s incentive compensation plan. During the nine months ended September 30, 2013, Calamos Investments repurchased 904,350 Class A common stock, at an average purchase price of $10.74 and a total cost of $9.7 million. As Calamos Investments is consolidated with CAM, the repurchased shares are reported as treasury shares.  As such, CAM’s 22.2% ownership interest in these shares totaling $2.2 million is reported in treasury stock, with Calamos Interests’ 77.8% ownership interest in these shares totaling $7.6 million reported in non-controlling interest in the consolidated statements of financial condition. The total shares repurchased are not included in the calculation of basic and diluted earnings per share in accordance with GAAP.
	During the third quarter of 2013, CAM redeemed 7,136 Class A common shares from Calamos Investments for a value of $77,000 which represents the fair value of the shares on the date of redemption. As Calamos Investments is consolidated with CAM, the impact of the distribution reflecting the non-controlling interest is $60,000.
	During the third quarter and nine months ended September 30, 2013, dividends on shares held by Calamos Investments totaled $112,000 and $171,000, respectively. The payment of these dividends increased Calamos Investments' equity resulting in a $87,000 adjustment for the third quarter, and a $133,000 adjustment for the nine months ended September 30, 2013 from additional paid in capital to non-controlling interest in Calamos Investments LLC, in the consolidated statement of changes in stockholders' equity. This adjustment represents Calamos Interests' ownership interest in those dividend payments.
Investment Securities	'
	Investment Securities
	Investment securities that are available-for-sale are evaluated for other-than-temporary impairment on a quarterly basis when the cost of an investment exceeds its fair value. When evaluating these securities, we consider many factors, including the duration of the impairment, the severity of the impairment, subsequent changes in value, the Company's intent and ability to hold these securities for a period of time sufficient to allow for recovery of the market value, and the nature of the securities held. When an impairment of an equity security is determined to be other-than-temporary, the impairment is recognized in earnings. See Note 3, Investment Securities for more discussion related to the other-than-temporary impairment charge recorded in the second quarter of 2013.
Income Taxes	'
	Income Taxes
	Deferred tax assets and liabilities are recognized for the future tax consequences attributable to the temporary differences between the financial statement carrying amount of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. During the second quarter ended June 30, 2013, the Company recorded a valuation allowance to reduce its deferred income tax assets to an amount that is more likely than not to be realized based on available evidence at the time the estimate was made. No additional adjustment to the valuation allowances was made in the third quarter ended September 30, 2013. Determining a valuation allowance requires management to make significant judgments and assumptions. In determining a valuation allowance the Company uses historical and forecasted future realized and unrealized gains and losses on its investment, ongoing tax planning strategies, and forecasts of future taxable income. Each quarter, the Company re-evaluates its estimates related to its valuation allowance, including its assumptions about future taxable income. Applying its tax harvesting strategies, the Company's capital loss carryforward is used against realized gains on its investment, derivative assets, derivative liabilities and partnership investments. See Note 10, Income Taxes for more discussion related to the deferred tax valuation allowance.

Investment_Securities_Tables

Investment Securities (Tables)	9 Months Ended
	Sep. 30, 2013
Investments [Abstract]	'
Summary of investment securities	'
	The following tables provide a summary of investment securities owned by the Company as of September 30, 2013 and December 31, 2012:
		September 30, 2013
	(in thousands)
					Unrealized			Unrealized
		Cost			Gains			Losses			Fair Value
	Available-for-sale securities:
	Funds
	Equity	$	212,069		$	12,257		$	(1	)	$	224,325
	Fixed income	105,443			291			(2,844		)	102,890
	Lower-volatility equity	45,501			1,950			—			47,451
	Alternative	35,269			192			—			35,461
	Other	1,385			65			(10		)	1,440
	Total Funds	399,667			14,755			(2,855		)	411,567
	Common stock	132			39			—			171
	Total available-for-sale securities	$	399,799		$	14,794		$	(2,855	)	$	411,738
	CFS securities:
	Total CFS securities	$	3,913		$	424		$	—		$	4,337
	Total investment securities										$	416,075
		December 31, 2012
	(in thousands)
					Unrealized			Unrealized
		Cost			Gains			Losses			Fair Value
	Available-for-sale securities:
	Funds
	Equity	$	195,553		$	2,930		$	(5,517	)	$	192,966
	Fixed income	103,404			665			(957		)	103,112
	Lower-volatility equity	43,718			106			(484		)	43,340
	Alternative	5,058			2			(92		)	4,968
	Other	1,543			42			(270		)	1,315
	Total Funds	349,276			3,745			(7,320		)	345,701
	Common stock	131			1			—			132
	Total available-for-sale securities	$	349,407		$	3,746		$	(7,320	)	$	345,833
	CFS securities:
	Total CFS securities	$	3,004		$	567		$	—		$	3,571
	Total investment securities										$	349,404
Summary of changes in unrealized gains and losses on investment securities	'
	The table below summarizes information on available-for-sale securities as well as the change in unrealized gains and losses on CFS securities for the three and nine months ended September 30, 2013 and 2012:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2013			2012			2013			2012
	(in thousands)
	Available-for-sale securities:
	Proceeds from sale	$	77,465		$	54,162		$	325,447		$	330,678
	Gross realized gains on sales	$	2,833		$	1,833		$	10,171		$	28,273
	CFS securities:
	Change in unrealized gains (losses)	$	429		$	153		$	(143	)	$	318
Summary of tax (provision) benefit on unrealized gains	'
	The tables below summarize the tax (provision) benefit on unrealized gains and gains reclassified out of accumulated other comprehensive income on available-for-sale securities for the three and nine months ended September 30, 2013 and 2012:
		Three Months Ended									Three Months Ended
		September 30, 2013									September 30, 2012
	(in thousands)	Before-Tax Amount			Tax Provision			After-Tax			Before-Tax Amount			Tax Provision			After-Tax
								Amount									Amount
	Available-for-sale securities:
	Changes in unrealized gains	$	20,094		$	(1,823	)	$	18,271		$	15,115		$	(1,234	)	$	13,881
	Reclassification adjustment for realized losses included in income	610			(51		)	559			534			(42		)	492
	Other comprehensive income	$	20,704		$	(1,874	)	$	18,830		$	15,649		$	(1,276	)	$	14,373
		Nine Months Ended									Nine Months Ended
		September 30, 2013									September 30, 2012
	(in thousands)	Before-Tax Amount			Tax (Provision) Benefit			After-Tax			Before-Tax Amount			Tax (Provision) Benefit			After-Tax
								Amount									Amount
	Available-for-sale securities:
	Changes in unrealized gains	$	20,485		$	(1,724	)	$	18,761		$	21,469		$	(1,753	)	$	19,716
	Reclassification adjustment for realized gains included in income	(4,973		)	408			(4,565		)	(20,040		)	1,637			(18,403		)
	Other comprehensive income	$	15,512		$	(1,316	)	$	14,196		$	1,429		$	(116	)	$	1,313

Partnership_Investments_Tables

Partnership Investments (Tables)	9 Months Ended
	Sep. 30, 2013
Partnership Investments [Abstract]	'
Partnership Investments	'
	These investments are presented collectively as partnership investments, net in the consolidated statements of financial condition as of September 30, 2013 and December 31, 2012.
	(in thousands)	September 30, 2013			December 31, 2012
	Consolidated partnership:
	Securities owned	$	35,118		$	30,910
	Cash and cash equivalents	16,698			12,720
	Receivables for securities sold	269			—
	Other current assets	324			743
	Exchange-traded option contracts	85			13
	Securities sold not yet purchased	(7,817		)	(5,746		)
	Payables for securities purchased	(997		)	—
	Accrued expenses and other current liabilities	(308		)	(739		)
	Total	43,372			37,901
	Equity method investment in partnerships	3,637			22,927
	Partnership investments, net	$	47,009		$	60,828

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair value of assets and liabilities measured on recurring basis	'
	The following tables provide the hierarchy of inputs used to derive the fair value of the Company’s assets and liabilities measured at fair value on a recurring basis as of September 30, 2013 and December 31, 2012, respectively. Foreign currency contracts are carried in our partnership investments and are presented on a net basis where the right of offset exists. There were no material foreign currency contracts for either period presented.
					Fair Value Measurements Using
		September 30, 2013			Quoted Prices
					in Active			Significant
	(in thousands)				Markets for			Other
	Description				Identical Assets			Observable
					and Liabilities			Inputs
					(Level 1)			(Level 2)
	Cash and cash equivalents
	Money market funds	$	3,810		$	3,810		$	—
	Investment securities (Note 3)
	Funds
	Equity	228,664			228,664			—
	Fixed income	102,890			102,890			—
	Lower-volatility equity	47,451			47,451			—
	Alternative	35,461			35,461			—
	Other	1,440			1,440			—
	Total Funds	415,906			415,906			—
	Common stock	171			171			—
	Investment securities	416,077			416,077			—
	Derivative assets (Note 4)
	Exchange-traded put option contracts	—			—			—
	Securities and derivatives owned by partnership (Note 5)
	Common stocks	34,789			23,988			10,801
	Preferred stocks	151			—			151
	Short term investments	270			—			270
	Exchange-traded put option contracts	315			315			—
		35,525			24,303			11,222
	Securities sold but not yet purchased by partnership (Note 5)
	Common stocks	(7,796		)	(7,796		)	—
	Exchange-traded call option contracts	(74		)	(74		)	—
	Forward foreign currency contracts	—			—			—
	Securities sold but not yet purchased (Note 3)
	Common stocks	(2		)	(2		)	—
		(7,872		)	(7,872		)	—
	Total	$	447,540		$	436,318		$	11,222
					Fair Value Measurements Using
		December 31, 2012			Quoted Prices
	(in thousands)				in Active			Significant
	Description				Markets for			Other
					Identical Assets			Observable
					and Liabilities			Inputs
					(Level 1)			(Level 2)
	Cash and cash equivalents
	Money market funds	$	2,700		$	2,700		$	—
	Investment securities (Note 3)
	Funds
	Equity	196,537			196,537			—
	Fixed income	103,112			103,112			—
	Lower-volatility equity	43,340			43,340			—
	Alternative	6,062			6,062			—
	Other	1,315			1,315			—
	Total Funds	350,366			350,366			—
	Common stock	132			132			—
	Investment securities	350,498			350,498			—
	Derivative assets (Note 4)
	Exchange-traded put option contracts	132			132			—
	Securities and derivatives owned by partnership (Note 5)
	Common stocks	29,742			20,105			9,637
	Preferred stocks	1,167			1,167			—
	Short term investments	467			—			467
	Exchange-traded put option contracts	75			75			—
	Forward foreign currency contracts	45			45			—
	31,496			21,392			10,104
Securities sold but not yet purchased by partnership (Note 5)
Common stocks
Common stocks	(5,746		)	(5,746		)	—
Exchange-traded call option contracts	(62		)	(62		)	—
Forward foreign currency contracts	(45		)	(45		)	—
Securities sold but not yet purchased (Note 3)
Common stocks	(1,094		)	(1,094		)	—
	(6,947		)	(6,947		)	—
Total	$	377,879		$	367,775		$	10,104

NonOperating_Income_Tables

Non-Operating Income (Tables)	9 Months Ended
	Sep. 30, 2013
Other Income and Expenses [Abstract]	'
Non-operating income	'
	Non-operating income was comprised of the following components for the three and nine months ended September 30, 2013 and 2012:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
	(in thousands)
	Interest income	$	49		$	107		$	209		$	291
	Interest expense	(1,505		)	(1,503		)	(4,516		)	(4,511		)
	Net interest expense	(1,456		)	(1,396		)	(4,307		)	(4,220		)
	Investment income	5,603			3,187			9,086			22,811
	Dividend income	1,020			877			2,755			2,453
	Miscellaneous other income	163			88			287			244
	Investment and other income	6,786			4,152			12,128			25,508
	Non-operating income	$	5,330		$	2,756		$	7,821		$	21,288

Income_Taxes_Tables

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Schedule of components of income tax expense (benefit)	'
	Calamos Investments is subject to certain income-based state taxes; therefore, income taxes reflect not only the portion attributed to CAM stockholders but also a portion of income taxes attributable to non-controlling interests.
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
	(in thousands)
	Income tax provision	$	1,603		$	2,314		$	6,154		$	10,879
	Income tax (provision) benefit attributable to non-controlling interest in Calamos Investments	10			377			(37		)	183
	Income tax provision attributable to CAM	1,613			2,691			6,117			11,062
	Net income attributable to CAM	2,697			4,733			7,772			13,586
	Income before taxes attributable to CAM	$	4,310		$	7,424		$	13,889		$	24,648
	CAM’s effective income tax rate	37.4		%	36.2		%	44		%	44.9		%

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Calculation of basic and diluted earnings per share	'
	The following table reflects the calculation of basic and diluted earnings per share:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(in thousands, except per share data)	2013			2012			2013		2012
	Earnings per share – basic
	Earnings available to common shareholders	$	2,697		$	4,733		$	7,772	$	13,586
	Weighted average shares outstanding	19,672			20,374			19,999		20,317
	Earnings per share – basic	$	0.14		$	0.23		$	0.39	$	0.67
	Earnings per share – diluted
	Earnings available to common shareholders	$	2,697		$	4,733		$	7,772	$	13,586
	Weighted average shares outstanding	19,672			20,374			19,999		20,317
	Dilutive impact of restricted stock units	716			429			601		381
	Weighted average diluted shares outstanding	20,388			20,803			20,600		20,698
	Earnings per share – diluted	$	0.13		$	0.23		$	0.38	$	0.66
Schedule of antidilutive securities excluded from computation of earnings per share	'
	The following table shows the number of shares which were excluded from the computation of diluted earnings per share as they were anti-dilutive:
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2013		2012			2013		2012
	Exchange of Calamos Interests’ ownership in Calamos Investments for shares of Class A common stock	31,877,237		41,710,042			31,877,237		41,710,042
	Restricted stock units	—		6,934			—		—
	Stock options	2,101,568		2,196,591			2,101,568		2,196,591
	Total	33,978,805		43,913,567			33,978,805		43,906,633

Organization_and_Description_o1

Organization and Description of Business (Details)	9 Months Ended
	Sep. 30, 2013		Dec. 31, 2012
Corporate Structure [Line Items]	'		'
Percentage of ownership interest held by Calamos Family Partners, Inc. (in hundredths)	77.80%	[1]	77.90%
Options and RSU awards vesting period	'60 days		'
Class A Common Stock [Member]	'		'
Corporate Structure [Line Items]	'		'
Percentage of ownership (including vested stock options) by noncontrolling owners (in hundredths)	11.88%		'
Class A Common Stock [Member] | Public Stockholders [Member]	'		'
Corporate Structure [Line Items]	'		'
Percentage of public shareholders voting power (in hundredths)	2.60%	[2]	'
Class A Common Stock [Member] | Public Stockholders [Member] | Minimum [Member]	'		'
Corporate Structure [Line Items]	'		'
Percentage of public shareholders economic interest (in hundredths)	99.00%	[2]	'
Calamos Asset Management, Inc. [Member]	'		'
Corporate Structure [Line Items]	'		'
Percentage of ownership (in hundredths)	22.20%		'
Calamos Family Partners, Inc. [Member] | Class B Common Stock [Member]	'		'
Corporate Structure [Line Items]	'		'
Percentage of voting power owned in Calamos Asset Management (in hundredths)	97.40%		'
Calamos Family Partners, Inc. [Member] | Class B Common Stock [Member] | Maximum [Member]	'		'
Corporate Structure [Line Items]	'		'
Percentage of economic interest (in hundredths)	1.00%		'
[1]	Represents combined economic interest of Calamos Family Partners, Inc. and John P. Calamos, Sr. who is also a member of Calamos Investments LLC.
[2]	Represents combined economic interest of all public stockholders, including John P. Calamos, Sr., Nick Calamos and John P. Calamos, Jr.bs combinedB 11.88% ownership interest of Class A common stock. The calculation of ownership interest includes options and RSUs that vest within 60 days, as well as CFPbs ownership interest in Class A common stock purchased by Calamos Investments, pursuant to the Companybs share repurchase plan.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2013		Dec. 31, 2012
Accounting Policies [Abstract]	'		'		'
Equity method investment, ownership percentage, maximum (in hundredths)	50.00%		50.00%		'
Percentage of combined interest in subsidiary that is considered to be noncontrolling interest (in hundredths)	77.80%	[1]	77.80%	[1]	77.90%
Restricted Cash [Abstract]	'		'		'
Restricted cash	$430		$430		'
Equity, Class of Treasury Stock [Line Items]	'		'		'
Period over which shares can be repurchased	'		'2 years		'
Total cost of repurchase of common stock	'		9,717		'
Stock distributed, value	'		0		'
Dividends paid to subsidiary	112		171		'
Impact on non-controlling interest as a result of dividends paid to Calamos Investments LLC on repurchased common stock	'		0		'
Treasury Stock [Member]	'		'		'
Equity, Class of Treasury Stock [Line Items]	'		'		'
Total cost of repurchase of common stock	'		2,157		'
Stock distributed, value	'		0		'
Impact on non-controlling interest as a result of dividends paid to Calamos Investments LLC on repurchased common stock	'		0		'
Noncontrolling Interest in Calamos Investments LLC (Calamos Interests) [Member]	'		'		'
Equity, Class of Treasury Stock [Line Items]	'		'		'
Total cost of repurchase of common stock	'		7,560		'
Stock distributed, value	'		0		'
Impact on non-controlling interest as a result of dividends paid to Calamos Investments LLC on repurchased common stock	87		133		'
Calamos Asset Management, Inc. [Member]	'		'		'
Equity, Class of Treasury Stock [Line Items]	'		'		'
Percentage of ownership (in hundredths)	'		22.20%		'
Class A Common Stock [Member]	'		'		'
Equity, Class of Treasury Stock [Line Items]	'		'		'
Number of shares authorized to be repurchased (in shares)	3,000,000		3,000,000		'
Repurchase of common stock (in shares)	'		904,350		'
Average purchase price per share (in dollars per share)	'		$10.74		'
Total cost of repurchase of common stock	'		9,700		'
Stock distributed (in shares)	'		151,692		'
Class A Common Stock [Member] | Calamos Asset Management, Inc. [Member]	'		'		'
Equity, Class of Treasury Stock [Line Items]	'		'		'
Stock distributed (in shares)	7,136		'		'
Stock distributed, value	77		'		'
Class A Common Stock [Member] | Calamos Asset Management, Inc. [Member] | Noncontrolling Interest [Member]	'		'		'
Equity, Class of Treasury Stock [Line Items]	'		'		'
Stock distributed, value	$60		'		'
[1]	Represents combined economic interest of Calamos Family Partners, Inc. and John P. Calamos, Sr. who is also a member of Calamos Investments LLC.

Investment_Securities_Details

Investment Securities (Details) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Summary of investment securities [Abstract]	'	'	'	'	'	'
CFS Securities, cost	$3,913,000	'	'	$3,913,000	'	$3,004,000
Trading securities, Unrealized Gain	424,000	'	'	424,000	'	567,000
Trading Securities, Unrealized Loss	0	'	'	0	'	0
CFS Securities, fair value	4,337,000	'	'	4,337,000	'	3,571,000
Total investment securities	416,075,000	'	'	416,075,000	'	349,404,000
Investments in funds	415,900,000	'	'	415,900,000	'	349,300,000
Investments in affiliated funds	364,600,000	'	'	364,600,000	'	295,000,000
Aggregate fair value of available-for-sale securities in unrealized loss position	79,800,000	'	'	79,800,000	'	251,300,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	'	'	0	'	123,900,000
Period for which the losses on securities were continuous	'	'	'	'12 months	'	'
Other than Temporary Impairment Losses, Investments	'	4,400,000	'	'	'	'
Available-for-sale securities:	'	'	'	'	'	'
Proceeds from sale	77,465,000	'	54,162,000	325,447,000	330,678,000	'
Gross realized gains on sales	2,833,000	'	1,833,000	10,171,000	28,273,000	'
CFS securities:	'	'	'	'	'	'
Change in unrealized gains (losses)	429,000	'	153,000	-143,000	318,000	'
Available-for-sale securities [Abstract]	'	'	'	'	'	'
Changes in unrealized losses (Before-Tax Amount)	20,094,000	'	15,115,000	20,485,000	21,469,000	'
Change in unrealized gains (losses), Tax (Provision) Benefit	-1,823,000	'	-1,234,000	-1,724,000	-1,753,000	'
Change in unrealized gains (losses), After-Tax Amount	18,271,000	'	13,881,000	18,761,000	19,716,000	'
Reclassification adjustment for realized gains included in income (Before-Tax Amount)	610,000	'	534,000	-4,973,000	-20,040,000	'
Reclassification adjustment for realized gains included in income, Tax (Provision) Benefit	-51,000	'	-42,000	408,000	1,637,000	'
Reclassification adjustment for realized gains included in income, After-Tax Amount	559,000	'	492,000	-4,565,000	-18,403,000	'
Other comprehensive income, before income tax provision	20,704,000	'	15,649,000	15,512,000	1,429,000	'
Other comprehensive income (loss), Tax (Provision) Benefit	-1,874,000	'	-1,276,000	-1,316,000	-116,000	'
Other comprehensive income, after income tax provision	18,830,000	'	14,373,000	14,196,000	1,313,000	'
Available-For-Sale Securities [Member]	'	'	'	'	'	'
Summary of investment securities [Abstract]	'	'	'	'	'	'
Available-for-sale securities, cost	399,799,000	'	'	399,799,000	'	349,407,000
Available-for-sale securities, Unrealized Gains	14,794,000	'	'	14,794,000	'	3,746,000
Available-for-sale securities, Unrealized Losses	-2,855,000	'	'	-2,855,000	'	-7,320,000
Available-for-sale securities, Fair Value	411,738,000	'	'	411,738,000	'	345,833,000
Available-For-Sale Securities [Member] | Equity [Member]	'	'	'	'	'	'
Summary of investment securities [Abstract]	'	'	'	'	'	'
Available-for-sale securities, cost	212,069,000	'	'	212,069,000	'	195,553,000
Available-for-sale securities, Unrealized Gains	12,257,000	'	'	12,257,000	'	2,930,000
Available-for-sale securities, Unrealized Losses	-1,000	'	'	-1,000	'	-5,517,000
Available-for-sale securities, Fair Value	224,325,000	'	'	224,325,000	'	192,966,000
Available-For-Sale Securities [Member] | Fixed Income [Member]	'	'	'	'	'	'
Summary of investment securities [Abstract]	'	'	'	'	'	'
Available-for-sale securities, cost	105,443,000	'	'	105,443,000	'	103,404,000
Available-for-sale securities, Unrealized Gains	291,000	'	'	291,000	'	665,000
Available-for-sale securities, Unrealized Losses	-2,844,000	'	'	-2,844,000	'	-957,000
Available-for-sale securities, Fair Value	102,890,000	'	'	102,890,000	'	103,112,000
Available-For-Sale Securities [Member] | Low-Volatility Equity [Member]	'	'	'	'	'	'
Summary of investment securities [Abstract]	'	'	'	'	'	'
Available-for-sale securities, cost	45,501,000	'	'	45,501,000	'	43,718,000
Available-for-sale securities, Unrealized Gains	1,950,000	'	'	1,950,000	'	106,000
Available-for-sale securities, Unrealized Losses	0	'	'	0	'	-484,000
Available-for-sale securities, Fair Value	47,451,000	'	'	47,451,000	'	43,340,000
Available-For-Sale Securities [Member] | Alternative [Member]	'	'	'	'	'	'
Summary of investment securities [Abstract]	'	'	'	'	'	'
Available-for-sale securities, cost	35,269,000	'	'	35,269,000	'	5,058,000
Available-for-sale securities, Unrealized Gains	192,000	'	'	192,000	'	2,000
Available-for-sale securities, Unrealized Losses	0	'	'	0	'	-92,000
Available-for-sale securities, Fair Value	35,461,000	'	'	35,461,000	'	4,968,000
Available-For-Sale Securities [Member] | Other [Member]	'	'	'	'	'	'
Summary of investment securities [Abstract]	'	'	'	'	'	'
Available-for-sale securities, cost	1,385,000	'	'	1,385,000	'	1,543,000
Available-for-sale securities, Unrealized Gains	65,000	'	'	65,000	'	42,000
Available-for-sale securities, Unrealized Losses	-10,000	'	'	-10,000	'	-270,000
Available-for-sale securities, Fair Value	1,440,000	'	'	1,440,000	'	1,315,000
Available-For-Sale Securities [Member] | Total Funds [Member]	'	'	'	'	'	'
Summary of investment securities [Abstract]	'	'	'	'	'	'
Available-for-sale securities, cost	399,667,000	'	'	399,667,000	'	349,276,000
Available-for-sale securities, Unrealized Gains	14,755,000	'	'	14,755,000	'	3,745,000
Available-for-sale securities, Unrealized Losses	-2,855,000	'	'	-2,855,000	'	-7,320,000
Available-for-sale securities, Fair Value	411,567,000	'	'	411,567,000	'	345,701,000
Available-For-Sale Securities [Member] | Common Stock [Member]	'	'	'	'	'	'
Summary of investment securities [Abstract]	'	'	'	'	'	'
Available-for-sale securities, cost	132,000	'	'	132,000	'	131,000
Available-for-sale securities, Unrealized Gains	39,000	'	'	39,000	'	1,000
Available-for-sale securities, Unrealized Losses	0	'	'	0	'	0
Available-for-sale securities, Fair Value	$171,000	'	'	$171,000	'	$132,000

Derivative_Assets_and_Liabilit1

Derivative Assets and Liabilities (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'	'	'	'	'
Total investment securities	$416,075	'	$416,075	'	$349,404
Net loss on derivatives	$0	$108	$1,900	$8,200	'

Partnership_Investments_Detail

Partnership Investments (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Dec. 31, 2012	Mar. 31, 2013
			Consolidated Partnerships [Member]	Consolidated Partnerships [Member]	Calamos Global Opportunities Fund LP [Member]
Other Ownership Interests [Line Items]	'	'	'	'	'
Total investment securities	$416,075,000	$349,404,000	'	'	'
Consolidated partnership [Abstract]	'	'	'	'	'
Securities owned	'	'	35,118,000	30,910,000	'
Cash and cash equivalents	'	'	16,698,000	12,720,000	'
Receivables for securities sold	'	'	269,000	0	'
Other current assets	'	'	324,000	743,000	'
Exchange-traded option contracts	'	'	85,000	13,000	'
Securities sold not yet purchased	'	'	-7,817,000	-5,746,000	'
Payables for securities purchased	'	'	-997,000	0	'
Accrued expenses and other current liabilities	'	'	-308,000	-739,000	'
Total	'	'	43,372,000	37,901,000	'
Equity method investment in partnerships	'	'	3,637,000	22,927,000	'
Partnership investments, net	'	'	47,009,000	60,828,000	'
Liquidated interest value	'	'	'	'	18,700,000
Proceeds from sale of investments	'	'	'	'	20,000,000
Realized capital gains on sale of investments	'	'	'	'	$1,300,000

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member]	'	'
Cash and cash equivalents [Abstract]	'	'
Money market funds	$3,810,000	$2,700,000
Investment securities owned (Note 3) [Abstract]	'	'
Equity	228,664,000	196,537,000
Fixed income	102,890,000	103,112,000
Lower-volatility equity	47,451,000	43,340,000
Alternative	35,461,000	6,062,000
Other	1,440,000	1,315,000
Total Funds	415,906,000	350,366,000
Common stock	171,000	132,000
Investment securities	416,077,000	350,498,000
Derivative assets (Note 4) [Abstract]	'	'
Exchange-traded put option contracts	0	132,000
Securities and derivatives owned by partnership (Note 5) [Abstract]	'	'
Common stocks	23,988,000	20,105,000
Preferred stocks	0	1,167,000
Short term investments	0	0
Exchange-traded put option contracts	315,000	75,000
Forward foreign currency contracts	'	45,000
Securities and derivatives owned by partnership	24,303,000	21,392,000
Securities sold but not yet purchased by partnership (Note 5) [Abstract]	'	'
Common stocks	-7,796,000	-5,746,000
Financial Instruments Sold, Not yet Purchased, Derivatives and Other Contracts	-74,000	-62,000
Forward foreign currency contracts	0	-45,000
Securities sold but not yet purchased (Note 3) [Abstract]	'	'
Common stocks	-2,000	-1,094,000
Securities sold but not yet purchased by partnership	-7,872,000	-6,947,000
Total	436,318,000	367,775,000
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]	'	'
Cash and cash equivalents [Abstract]	'	'
Money market funds	0	0
Investment securities owned (Note 3) [Abstract]	'	'
Equity	0	0
Fixed income	0	0
Lower-volatility equity	0	0
Alternative	0	0
Other	0	0
Total Funds	0	0
Common stock	0	0
Investment securities	0	0
Derivative assets (Note 4) [Abstract]	'	'
Exchange-traded put option contracts	0	0
Securities and derivatives owned by partnership (Note 5) [Abstract]	'	'
Common stocks	10,801,000	9,637,000
Preferred stocks	151,000	0
Short term investments	270,000	467,000
Exchange-traded put option contracts	0	0
Forward foreign currency contracts	'	0
Securities and derivatives owned by partnership	11,222,000	10,104,000
Securities sold but not yet purchased by partnership (Note 5) [Abstract]	'	'
Common stocks	0	0
Financial Instruments Sold, Not yet Purchased, Derivatives and Other Contracts	0	0
Forward foreign currency contracts	0	0
Securities sold but not yet purchased (Note 3) [Abstract]	'	'
Common stocks	0	0
Securities sold but not yet purchased by partnership	0	0
Total	11,222,000	10,104,000
Recurring [Member] | Carrying Value [Member]	'	'
Cash and cash equivalents [Abstract]	'	'
Money market funds	3,810,000	2,700,000
Investment securities owned (Note 3) [Abstract]	'	'
Equity	228,664,000	196,537,000
Fixed income	102,890,000	103,112,000
Lower-volatility equity	47,451,000	43,340,000
Alternative	35,461,000	6,062,000
Other	1,440,000	1,315,000
Total Funds	415,906,000	350,366,000
Common stock	171,000	132,000
Investment securities	416,077,000	350,498,000
Derivative assets (Note 4) [Abstract]	'	'
Exchange-traded put option contracts	0	132,000
Securities and derivatives owned by partnership (Note 5) [Abstract]	'	'
Common stocks	34,789,000	29,742,000
Preferred stocks	151,000	1,167,000
Short term investments	270,000	467,000
Exchange-traded put option contracts	315,000	75,000
Forward foreign currency contracts	'	45,000
Securities and derivatives owned by partnership	35,525,000	31,496,000
Securities sold but not yet purchased by partnership (Note 5) [Abstract]	'	'
Common stocks	-7,796,000	-5,746,000
Financial Instruments Sold, Not yet Purchased, Derivatives and Other Contracts	-74,000	-62,000
Forward foreign currency contracts	0	-45,000
Securities sold but not yet purchased (Note 3) [Abstract]	'	'
Common stocks	-2,000	-1,094,000
Securities sold but not yet purchased by partnership	-7,872,000	-6,947,000
Total	447,540,000	377,879,000
Nonrecurring [Member] | Significant Other Observable Inputs (Level 2) [Member]	'	'
Securities sold but not yet purchased (Note 3) [Abstract]	'	'
Carrying value of long-term debt	92,100,000	92,100,000
Long-term debt fair value	104,400,000	110,100,000
Payment obligation fair value	3,300,000	3,200,000
Payment obligation associated with acquisition	$3,400,000	$3,400,000

Loans_Payable_Details

Loans Payable (Details) (Margin Loan [Member])	Sep. 30, 2013
Margin Loan [Member]	'
Short-term Debt [Line Items]	'
Margin loan interest rate effective percentage rate (in hundredths)	2.50%
Percentage of borrowing upon marginal securities, maximum (in hundredths)	70.00%

Stock_Based_Compensation_Detai

Stock Based Compensation (Details) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Compensation expense recorded in connection with RSUs and stock options	$4,887,000	$3,300,000
Deferred tax assets	401,000	269,000
Total unrecognized compensation expense	19,600,000	'
Unrecognized compensation expense, expected weighted-average period to be recognized	'3 years 4 months 24 days	'
Additional Paid-in Capital [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Compensation expense recognized under stock incentive plans credited to additional paid-in capital	1,084,000	726,000
RSU [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock units, granted (in shares)	838,663	'
Restricted stock units, forfeited (in shares)	403,873	'
Restricted stock units, vested (in shares)	178,903	'
Number of RSUs withheld for taxes (in shares)	27,211	'
Number of RSUs converted on a one-for-one basis for shares of company's Class A common stock (in shares)	151,692	'
Total intrinsic value and fair value of converted shares	1,700,000	'
Total tax benefit realized in connection with the vesting of RSUs	$184,000	'
Stock Options [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Stock options granted (in shares)	0	'
Stock options forfeited (in shares)	93,846	'

NonOperating_Income_Details

Non-Operating Income (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other Income and Expenses [Abstract]	'	'	'	'
Interest income	$49	$107	$209	$291
Interest expense	-1,505	-1,503	-4,516	-4,511
Net interest expense	-1,456	-1,396	-4,307	-4,220
Investment income	5,603	3,187	9,086	22,811
Dividend income	1,020	877	2,755	2,453
Miscellaneous other income	163	88	287	244
Investment and other income	6,786	4,152	12,128	25,508
Total non-operating income (loss)	$5,330	$2,756	$7,821	$21,288

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Income tax expense (benefit) [Abstract]	'	'	'	'	'
Income tax provision	$1,603,000	$2,314,000	$6,154,000	$10,879,000	'
Net income attributable to CAM	2,697,000	4,733,000	7,772,000	13,586,000	'
Income before taxes attributable to CAM	4,310,000	7,424,000	13,889,000	24,648,000	'
CAM's effective income tax rate (in hundredths)	37.40%	36.20%	44.00%	44.90%	'
Adjustedeffectivetaxrate (as a percent)	'	'	37.60%	37.20%	'
Capital loss carryforward	'	'	'	'	28,100,000
Amount of capital loss carry forward expiring in 2013	'	'	'	'	21,800,000
Amount of capital loss carry forward expiring in 2014	'	'	'	'	5,800,000
Amount of capital loss carry forward expiring in 2017	'	'	'	'	456,000
Valuation allowance	8,000,000	'	8,000,000	'	'
Increase in deferred tax asset valuation allowance	'	'	900,000	1,900,000	'
Non-controlling Interest in Calamos Investments LLC [Member]	'	'	'	'	'
Income tax expense (benefit) [Abstract]	'	'	'	'	'
Income tax provision	10,000	377,000	-37,000	183,000	'
Calamos Asset Management, Inc. [Member]	'	'	'	'	'
Income tax expense (benefit) [Abstract]	'	'	'	'	'
Income tax provision	$1,613,000	$2,691,000	$6,117,000	$11,062,000	'

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings per share - basic [Abstract]	'	'	'	'
Earnings available to common shareholders	$2,697	$4,733	$7,772	$13,586
Weighted average shares outstanding (in shares)	19,671,742	20,373,585	19,998,922	20,316,901
Earnings per share - basic (in dollars per share)	$0.14	$0.23	$0.39	$0.67
Earnings per share - diluted [Abstract]	'	'	'	'
Earnings available to common shareholders	$2,697	$4,733	$7,772	$13,586
Weighted average shares outstanding (in shares)	19,671,742	20,373,585	19,998,922	20,316,901
Dilutive impact of restricted stock units (in shares)	716,000	429,000	601,000	381,000
Weighted average diluted shares outstanding (in shares)	20,387,651	20,802,592	20,599,821	20,698,105
Earnings per share - diluted (in dollars per share)	$0.13	$0.23	$0.38	$0.66
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Anti-dilutive (in shares)	33,978,805	43,913,567	33,978,805	43,906,633
Class A Common Stock [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Number of shares issuable to Calamos interests, maximum (in shares)	68,784,032	'	68,784,032	'
Ownership interest in Calamos Investments [Member] | Class A Common Stock [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Anti-dilutive (in shares)	31,877,237	41,710,042	31,877,237	41,710,042
Restricted stock units [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Anti-dilutive (in shares)	0	6,934	0	0
Stock Options [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Anti-dilutive (in shares)	2,101,568	2,196,591	2,101,568	2,196,591