Investments - Contractual Maturities (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Amortized Cost
Less: loaned securities	$ 79,073	$ 103,996
Total fixed-maturities available for sale	5,643,884	5,367,729
Fair Value
Less: loaned securities	79,073	103,996
Total fixed-maturities available for sale	5,228,744	5,517,078
Fixed-maturities available for sale \| Non asset-backed securities
Amortized Cost
Due in one year or less	151,491
Due after one year through five years	1,298,176
Due after five years through 10 years	1,112,921
Due after 10 years	849,400
Fair Value
Due in one year or less	150,543
Due after one year through five years	1,249,795
Due after five years through 10 years	1,001,606
Due after 10 years	710,723
Fixed-maturities available for sale \| Asset-backed and mortgage-backed securities
Amortized Cost
Asset-backed and mortgage-backed securities	2,248,024
Fair Value
Asset-backed and mortgage-backed securities	2,130,425
Fixed-maturities available for sale \| Total fixed-maturities available for sale
Amortized Cost
Total	5,660,012	5,430,898
Total fixed-maturities available for sale	5,643,884	5,367,729
Fair Value
Total	5,243,092	5,582,689
Total fixed-maturities available for sale	5,228,744	5,517,078
Fixed-maturities available for sale \| Loaned securities, amortized cost \| Total fixed-maturities available for sale
Amortized Cost
Less: loaned securities	16,128	63,169
Fair Value
Less: loaned securities	16,128	63,169
Fixed-maturities available for sale \| Loaned securities, fair value \| Total fixed-maturities available for sale
Amortized Cost
Less: loaned securities	14,348	65,611
Fair Value
Less: loaned securities	$ 14,348	$ 65,611

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