CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Total revenues	$ 259,726	$ 312,368
Expenses:
Compensation	102,347	123,528
Management fee	5,376	9,963
Distribution costs	28,474	34,226
Other operating expenses	23,920	26,667
Total expenses	160,117	194,384
Operating income	99,609	117,984
Non-operating income / (loss)
Loss from investments, net	(8,695)	(5,392)
Interest and dividend income	826	3,175
Interest expense	(2,620)	(2,609)
Shareholder-designated contribution	(5,436)	(4,500)
Total non-operating loss	(15,925)	(9,326)
Income before income taxes	83,684	108,658
Provision for income taxes	24,991	26,741
Net income	$ 58,693	$ 81,917
Net income per share attributable to GAMCO Investors, Inc.'s shareholders:
Basic (in dollars per share)	$ 2.21	$ 2.99
Diluted (in dollars per share)	$ 2.20	$ 2.98
Weighted average shares outstanding:
Basic (in shares)	26,571	27,407
Diluted (in shares)	26,680	27,479
Investment Advisory and Incentive Fees [Member]
Revenues:
Total revenues	$ 233,628	$ 279,090
Distribution Fees and Other Income [Member]
Revenues:
Total revenues	$ 26,098	$ 33,278