Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Reinsurance recoverable, allowance for credit losses	$ 6	$ 0
Amortized cost on fixed maturities trading investments	4,306,573	4,226,790
Cost - equity security trading investments	679,105	668,843
Cost - short-term investments	212,715	123,928
Fixed assets, accumulated depreciation	$ 314,718	$ 332,938
Common Stock
Common stock, shares authorized (in shares)	70,000,000	70,000,000
Common stock, shares issued (in shares)	55,371,000	55,371,000
Common stock, shares outstanding (in shares)	55,371,000	55,371,000