Nature of Operations and Basis of Presentation (Credit Losses) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jan. 01, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Investment income accrual period	6 months
Credit loss allowance for reinsurance receivables	$ 241	$ 38	$ 0