CONDENSED CONSOLIDATED STATEMENTS OF INCOME UNAUDITED (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues
Investment advisory and incentive fees	$ 288,480	$ 268,024	$ 231,269
Distribution fees and other income	44,848	44,816	32,511
Institutional research services	10,953	14,288	16,600
Total revenues	344,281	327,128	280,380
Expenses
Compensation	137,223	130,382	113,255
Stock based compensation	13,583	2,588	10,585
Management fee	13,018	12,270	12,013
Distribution costs	40,842	44,427	31,048
Other operating expenses	28,485	24,167	22,450
Total expenses	233,151	213,834	189,351
Operating income	111,130	113,294	91,029
Other income (expense)
Net gain from investments	22,741	5,549	24,888
Extinguishment of debt	(6,307)	2	(497)
Interest and dividend income	5,651	6,594	5,905
Interest expense	(15,899)	(14,997)	(11,984)
Total other income (expense), net	6,186	(2,852)	18,312
Income before income taxes	117,316	110,442	109,341
Income tax provision	41,721	40,767	39,326
Net income	75,595	69,675	70,015
Net income/(loss) attributable to noncontrolling interests	56	(7)	1,223
Net income attributable to GAMCO Investors, Inc.'s shareholders	$ 75,539	$ 69,682	$ 68,792
Net income attributable to GAMCO Investors, Inc.'s shareholders per share:
Basic (in dollars per share)	$ 2.87	$ 2.62	$ 2.55
Diluted (in dollars per share)	$ 2.86	$ 2.61	$ 2.52
Weighted average shares outstanding:
Basic (in shares)	26,283	26,636	26,959
Diluted (in shares)	26,436	26,724	28,348