Investments - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule of Investments [Line Items]
Consolidated Investment Companies	$ 10,860	$ 7,863
Domestic and Foreign Debt Securities
Schedule of Investments [Line Items]
Consolidated Investment Companies	20,900	39,200
Equity Securities - Small and Mid-Cap
Schedule of Investments [Line Items]
Consolidated Investment Companies		3,800
Separate Accounts
Schedule of Investments [Line Items]
Investments-affiliates and other	6,800	6,300
Separate Accounts | Domestic and Foreign Debt Securities
Schedule of Investments [Line Items]
Investments-affiliates and other	3,500	3,000
Separate Accounts | Equity
Schedule of Investments [Line Items]
Investments-affiliates and other	2,700	2,600
Federated Funds
Schedule of Investments [Line Items]
Investments-affiliates and other	$ 4,100	$ 1,600