Earnings Per Share Attributable to Federated Investors, Inc. Shareholders Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net income attributable to Federated Investors, Inc.		$ 44,131	$ 37,560	$ 122,197	$ 109,623
Less: Total income available to participating unvested restricted shareholders, basic	[1]	(1,691)	(1,467)	(4,837)	(4,334)
Less: Total income available to participating unvested restricted shareholders, diluted	[1]	(1,691)	(1,467)	(4,837)	(4,334)
Total net income attributable to Federated Common Stock (Basic)	[2]	42,440	36,093	117,360	105,289
Total net income attributable to Federated Common Stock (Diluted)	[2]	$ 42,440	$ 36,093	$ 117,360	$ 105,289
Basic weighted-average common shares outstanding		100,449	100,729	100,606	100,748
Dilutive potential shares from stock options		2	2	1	1
Diluted weighted-average common shares outstanding		100,451	100,731	100,607	100,749
Net income attributable to Federated Common Stock - Basic and Diluted	[2]	$ 0.42	$ 0.36	$ 1.17	$ 1.05

[1] Income available to participating unvested restricted shareholders includes dividends paid on unvested restricted shares and their proportionate share of undistributed earnings.

[2] Federated Common Stock excludes unvested restricted stock which are deemed participating securities in accordance with the two-class method of computing earnings per share.