Investments - Contractual Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Amortized Cost
Less: loaned securities	$ 112,139	$ 103,996
Total fixed-maturities, available for sale, Amortized Cost	5,587,261	5,367,729
Fair Value
Less: loaned securities	112,139	103,996
Fixed-maturities available for sale—at fair value (amortized cost of $5,587,261 and $5,367,729)	5,017,711	5,517,078
Total fixed-maturities available for sale \| Non asset-backed securities
Amortized Cost
Due in one year or less	111,909
Due after one year through five years	1,274,935
Due after five years through 10 years	989,545
Due after 10 years	854,097
Fair Value
Due in one year or less	110,443
Due after one year through five years	1,197,900
Due after five years through 10 years	857,164
Due after 10 years	665,067
Total fixed-maturities available for sale \| Asset-backed securities and mortgage-related assets
Amortized Cost
Asset-backed and mortgage-backed securities	2,412,973
Fair Value
Asset-backed and mortgage-backed securities	2,234,326
Total fixed-maturities available for sale \| Total fixed-maturities available for sale
Amortized Cost
Total	5,643,459	5,430,898
Total fixed-maturities, available for sale, Amortized Cost	5,587,261	5,367,729
Fair Value
Total	5,064,900	5,582,689
Fixed-maturities available for sale—at fair value (amortized cost of $5,587,261 and $5,367,729)	5,017,711	5,517,078
Loaned securities, amortized cost \| Total fixed-maturities available for sale \| Total fixed-maturities available for sale
Amortized Cost
Less: loaned securities	56,198	63,169
Fair Value
Less: loaned securities	56,198	63,169
Loaned securities \| Total fixed-maturities available for sale
Amortized Cost
Less: loaned securities	47,200
Fair Value
Less: loaned securities	47,200
Loaned securities \| Total fixed-maturities available for sale \| Total fixed-maturities available for sale
Amortized Cost
Less: loaned securities	47,189	65,611
Fair Value
Less: loaned securities	$ 47,189	$ 65,611

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