Investments - Narrative (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Schedule of Investments [Line Items]
Investments—Affiliates and Other	$ 39,756	$ 26,935
Investments - Consolidated investment companies	55,007	64,526
Debt Securities
Schedule of Investments [Line Items]
Investments - Consolidated investment companies	29,100	38,900
Stocks of large U.S. and international companies
Schedule of Investments [Line Items]
Investments - Consolidated investment companies	22,100	22,600
Federated Hermes Funds
Schedule of Investments [Line Items]
Investments—Affiliates and Other	30,800	20,100
Separate Accounts
Schedule of Investments [Line Items]
Investments—Affiliates and Other	9,000	6,800
Separate Accounts | Debt Securities
Schedule of Investments [Line Items]
Investments—Affiliates and Other	5,300	2,600
Separate Accounts | Equity
Schedule of Investments [Line Items]
Investments—Affiliates and Other	$ 2,800	$ 3,000