Unaudited Interim Consolidated Statements of Financial Position (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Fixed maturities, available for sale, amortized cost	$ 5,624,060	$ 5,283,266
Fixed Maturities, Available-for-sale, allowance for credit losses	2,533
Fixed maturities, trading, amortized cost	73,413	59,995
Equity securities, at fair value	6,208	6,360
Commercial mortgage and other loans, allowance for credit losses	4,641	1,768
Other invested assets, at fair value	$ 101,549	$ 87,456
Common stock, par value (in dollars per share)	$ 10	$ 10
Common stock, shares authorized	1,000,000	1,000,000
Common stock, shares issued	250,000	250,000
Common stock, shares outstanding	250,000	250,000