CONDENSED CONSOLIDATED STATEMENTS OF INCOME UNAUDITED (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenues
Investment advisory and incentive fees	$ 77,443	$ 67,210	$ 150,050	$ 134,993
Distribution fees and other income	12,522	11,006	23,875	22,629
Institutional research services	2,325	2,808	4,546	5,151
Total revenues	92,290	81,024	178,471	162,773
Expenses
Compensation	37,759	32,921	73,411	67,475
Management fee	4,846	2,615	8,826	6,799
Distribution costs	11,871	10,012	22,881	20,189
Other operating expenses	6,030	5,109	10,842	10,931
Total expenses	60,506	50,657	115,960	105,394
Operating income	31,784	30,367	62,511	57,379
Other income (expense)
Net gain from investments	12,141	(4,171)	24,432	9,707
Interest and dividend income	2,507	1,782	3,852	3,018
Interest expense	(2,796)	(4,429)	(6,284)	(8,833)
Shareholder-designated contribution	0	0	(5,000)	0
Total other income, net	11,852	(6,818)	17,000	3,892
Income before income taxes	43,636	23,549	79,511	61,271
Income tax provision	15,724	8,686	28,919	22,442
Net income	27,912	14,863	50,592	38,829
Net income attributable to noncontrolling interests	19	(242)	154	(112)
Net income attributable to GAMCO Investors, Inc.'s shareholders	$ 27,893	$ 15,105	$ 50,438	$ 38,941
Net income attributable to GAMCO Investors, Inc.'s shareholders
Basic (in dollars per share)	$ 1.09	$ 0.58	$ 1.96	$ 1.48
Diluted (in dollars per share)	$ 1.09	$ 0.57	$ 1.96	$ 1.47
Weighted average shares outstanding:
Basic (in shares)	25,679	26,258	25,710	26,338
Diluted (in shares)	25,689	26,426	25,723	26,501
Dividends declared: (in dollars per share)	$ 0.05	$ 0.29	$ 0.10	$ 0.33