Investments - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Schedule of Investments [Line Items]
Investments—Affiliates and Other	$ 25,499	$ 26,935
Investments - Consolidated Investment Companies	47,162	64,526
Debt Securities
Schedule of Investments [Line Items]
Investments - Consolidated Investment Companies	28,700	38,900
Stocks of large U.S. and international companies
Schedule of Investments [Line Items]
Investments - Consolidated Investment Companies	15,800	22,600
Federated Hermes Funds
Schedule of Investments [Line Items]
Investments—Affiliates and Other	17,900	20,100
Separate Accounts
Schedule of Investments [Line Items]
Investments—Affiliates and Other	7,600	6,800
Separate Accounts | Debt Securities
Schedule of Investments [Line Items]
Investments—Affiliates and Other	4,400	2,600
Separate Accounts | Equity
Schedule of Investments [Line Items]
Investments—Affiliates and Other	$ 2,400	$ 3,000