Accumulated Other Comprehensive Income (Loss) Attributable to Federated Investors, Inc. Shareholders (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income (Loss), net of tax [Rollforward]
Balance, beginning of period	$ 857,121	$ 761,215
Other Comprehensive Income (Loss) Before Reclassifications and Tax	(13,670)	(4,257)
Reclassification Adjustment, before Tax		(322)
Tax Impact		102
Net Current-Period Other Comprehensive Income (Loss)	(13,670)	(4,477)
Balance, end of period	950,497	827,364
Unrealized Gain (Loss) on Equity Securities
Accumulated Other Comprehensive Income (Loss), net of tax [Rollforward]
Balance, beginning of period	0	29
Other Comprehensive Income (Loss) Before Reclassifications and Tax	0	0
Reclassification Adjustment, before Tax		(80)
Tax Impact		51
Net Current-Period Other Comprehensive Income (Loss)	0	(29)
Balance, end of period	0	0
Foreign Currency Translation Gain (Loss)
Accumulated Other Comprehensive Income (Loss), net of tax [Rollforward]
Balance, beginning of period	(14,617)	(819)
Other Comprehensive Income (Loss) Before Reclassifications and Tax	(13,670)	(4,257)
Reclassification Adjustment, before Tax		(242)
Tax Impact		51
Net Current-Period Other Comprehensive Income (Loss)	(13,670)	(4,448)
Balance, end of period	(28,287)	(5,267)
Total
Accumulated Other Comprehensive Income (Loss), net of tax [Rollforward]
Balance, beginning of period	(14,617)	(790)
Balance, end of period	$ (28,287)	$ (5,267)