CONDENSED CONSOLIDATED STATEMENTS OF INCOME UNAUDITED (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revenues
Investment advisory and incentive fees	$ 72,607	$ 67,783
Distribution fees and other income	11,353	11,623
Institutional research services	2,221	2,343
Total revenues	86,181	81,749
Expenses
Compensation	35,652	34,554
Management fee	3,980	4,184
Distribution costs	11,010	10,177
Other operating expenses	4,812	5,822
Total expenses	55,454	54,737
Operating income	30,727	27,012
Other income (expense)
Net gain from investments	12,291	13,878
Interest and dividend income	1,345	1,236
Interest expense	(3,488)	(4,404)
Shareholder-designated contribution	(5,000)	0
Total other income, net	5,148	10,710
Income before income taxes	35,875	37,722
Income tax provision	13,195	13,756
Net income	22,680	23,966
Net income attributable to noncontrolling interests	$ 135	$ 130
Net income attributable to GAMCO Investors, Inc.'s shareholders
Basic (in dollars per share)	$ 0.88	$ 0.90
Diluted (in dollars per share)	$ 0.88	$ 0.90
Weighted average shares outstanding:
Basic (in shares)	25,742	26,415
Diluted (in shares)	25,758	26,533
Dividends declared: (in dollars per share)	$ 0.05	$ 0.04