Consolidation (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 27, 2017	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Accounts receivable from Federated Funds		$ 27,400	$ 27,100
Fee Waivers		345,400	460,700
Investments—consolidated investment companies		45,411	58,072
Nonredeemable noncontrolling interest in subsidiary		0	958
Receivables		53,482	44,804
Financial Support, Fee Waivers [Member]
Variable Interest Entity [Line Items]
Nonconsolidated Legal Entity, Financial Support Amount		222,100	338,600
Financial Support, Capital Contributions [Member]
Variable Interest Entity [Line Items]
Nonconsolidated Legal Entity, Financial Support Amount		0	0
Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member]
Variable Interest Entity [Line Items]
Investments—consolidated investment companies		39,700	43,200
Redeemable noncontrolling interests in subsidiaries		27,700	28,300
Liabilities		400	700
Non-Consolidated Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Federated's maximum risk of loss in consolidated investment companies		900	2,300
AUM for nonconsolidated Federated Funds		55,800	76,300
Cash and Cash Equivalents [Member] | Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member]
Variable Interest Entity [Line Items]
Consolidated VIE assets		100	0
Trade Accounts Receivable [Member] | Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member]
Variable Interest Entity [Line Items]
Consolidated VIE assets		1,000	700
GeneralPartnershipandVIE [Member] | Passport [Member]
Variable Interest Entity [Line Items]
Noncontrolling interest, ownership percentage by parent	50.50%
Noncontrolling interest, ownership percentage by noncontrolling owners	49.50%
GeneralPartnershipandVIE [Member] | Deconsolidation [Member]
Variable Interest Entity [Line Items]
Liabilities	$ 5,300
Nonredeemable noncontrolling interest in subsidiary	1,000
GeneralPartnershipandVIE [Member] | Cash and Cash Equivalents [Member] | Deconsolidation [Member]
Variable Interest Entity [Line Items]
Consolidated VIE assets	4,800
GeneralPartnershipandVIE [Member] | Trade Accounts Receivable [Member] | Deconsolidation [Member]
Variable Interest Entity [Line Items]
Consolidated VIE assets	$ 2,600
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]
Variable Interest Entity [Line Items]
Investments—consolidated investment companies		5,700	14,900
Redeemable noncontrolling interests in subsidiaries		$ 2,500	$ 3,100