CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME UNAUDITED - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Comprehensive Income [Abstract]
Net income	$ 14,451	$ 20,552	$ 63,257	$ 77,851
Other comprehensive income, net of tax
Foreign currency translation	(35)	(45)	(22)	(15)
Net unrealized gains on securities available for sale, net of tax	(6,696)	(2,407)	(7,418)	(6,832)
Other comprehensive income	(6,731)	(2,452)	(7,440)	(6,847)
Comprehensive income	7,720	18,100	55,817	71,004
Less: Comprehensive income attributable to noncontrolling interests	518	3,113	589	2,718
Comprehensive income attributable to GAMCO Investors, Inc.	$ 8,238	$ 21,213	$ 56,406	$ 73,722