CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME UNAUDITED - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME UNAUDITED [Abstract]
Net income		$ 24,820	$ 26,025
Other comprehensive gain/(loss), net of tax:
Foreign currency translation		10	(28)
Net unrealized gain/(loss) on securities available for sale	[1]	(2,561)	2,583
Other comprehensive gain/(loss)		(2,551)	2,555
Comprehensive income attributable to GAMCO Investors, Inc.		$ 22,269	$ 28,580

[1] Net of income tax expense/(benefit) of ($1,504) and $1,517, respectively.