Document And Entity Information (USD $)	3 Months Ended
	Mar. 31, 2012	Apr. 30, 2012	Jun. 30, 2011
Entity Registrant Name	GAMCO INVESTORS, INC. ET AL
Entity Central Index Key	0001060349
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	No
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 307,699,443
Entity Common Stock, Shares Outstanding		6,592,716
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q1
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2012