Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Fixed-maturities available for sale, amortized cost	$ 5,599,111	$ 5,587,261
Trading securities, amortized cost	110,484	122,472
Equity securities, amortized cost	92,124	162,899
Reinvested cash collateral held under securities lending agreements	149,364	99,735
Reinsurance recoverables, paid losses	$ 59	$ 18
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)	173,247	176,509
Common stock, shares, outstanding (in shares)	153,179	157,056
Treasury stock (in shares)	20,068	19,453