Accumulated Other Comprehensive Income (Loss) Attributable to Federated Investors, Inc. Shareholders (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 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	(1,875)	(479)
Reclassification Adjustment, before Tax		(322)
Tax Impact		102
Net Current-Period Other Comprehensive Income (Loss)	(1,875)	(699)
Balance, end of period	912,528	799,125
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	(1,875)	(479)
Reclassification Adjustment, before Tax		(242)
Tax Impact		51
Net Current-Period Other Comprehensive Income (Loss)	(1,875)	(670)
Balance, end of period	(16,492)	(1,489)
Total
Accumulated Other Comprehensive Income (Loss), net of tax [Rollforward]
Balance, beginning of period	(14,617)	(790)
Balance, end of period	$ (16,492)	$ (1,489)