Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Fixed-maturities available for sale, amortized cost	$ 5,657,808	$ 5,599,111
Trading securities, amortized cost	109,275	110,484
Equity securities, cost	159,937	92,124
Reinvested cash collateral held under securities lending agreements	89,532	149,364
Reinsurance recoverables, paid losses	$ 164	$ 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)	171,588	173,247
Common stock, shares, outstanding (in shares)	151,509	153,179
Treasury stock (in shares)	20,079	20,068