Investments - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) security	Dec. 31, 2023 USD ($)
Investments
Accrued investment income	$ 28,319	$ 24,062
Number of debt securities for which there is an allowance for credit losses | security	8
Losses on fixed income securities		2,000
Number of debt securities in an unrealized loss position for which an allowance for credit losses has not been recorded | security	1,333
Unrealized loss	$ 224,611	214,396
Unrealized losses as percentage of fixed income portfolio cost basis	7.00%
Unrealized losses relative to total invested assets (as a percent)	5.00%
Number of unrealized loss positions | security	1,333
Number of securities in unrealized loss positions for 12 months or longer | security	1,009
Maximum
Investments
Losses on fixed income securities	$ 1,000
Fixed Income Securities
Investments
Accrued investment income	$ 27,000	$ 23,000