Investments - Amortized Cost and Estimated Fair Value, Net of Credit Loss Allowance, of Fixed Maturity Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Amortized cost
Due in one year or less	$ 45,052
Due after one year through five years	454,563
Due after five years through ten years	186,208
Due after ten years	380,133
Amortized cost	1,065,956
Held-to-maturity securities - due after ten years	4,833
Total fixed maturity securities, net	1,070,789
Estimated fair value
Due in one year or less	44,430
Due after one year through five years	451,762
Due after five years through ten years	185,333
Due after ten years	362,090
Total available-for-sale securities, net	1,043,615
Held-to-maturity securities - due after ten years	4,934
Total fixed maturity securities, net	1,048,549
Fair value of loaned securities	$ 7,285	$ 0