Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Statement of Financial Position [Abstract]
Fixed-maturities available for sale, amortized cost	$ 5,479,486	$ 5,511,501
Trading securities, amortized cost	81,520	89,479
Equity securities, cost	118,402	144,579
Reinvested cash collateral held under securities lending agreements	136,108	125,723
Reinsurance recoverables, paid losses	$ 528	$ 444
Common stock, par value (in usd per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	485,000	485,000
Common stock, shares, issued (in shares)	162,038	168,350
Common stock, shares, outstanding (in shares)	141,220	147,569
Treasury stock (in shares)	20,818	20,782