Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Fixed-maturities available for sale, amortized cost	$ 5,583,574	$ 5,599,111
Trading securities, amortized cost	91,976	110,484
Equity securities, cost	151,307	92,124
Reinvested cash collateral held under securities lending agreements	116,905	149,364
Reinsurance recoverables, paid losses	$ 369	$ 59
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)	170,541	173,247
Common stock, shares, outstanding (in shares)	149,776	153,179
Treasury stock (in shares)	20,766	20,068