Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Total fixed-maturities available for sale	$ 5,563,766	$ 5,367,729
Trading securities amortized cost	208,912	234,382
Equity securities, fair value cost	182,158	176,229
Reinvested cash collateral held under securities lending agreements	40,856	48,652
Reinsurance recoverables, paid losses	$ 17	$ 51
Common stock, par or stated value per share	$ 0.001	$ 0.001
Common stock, shares authorized	485,000,000	485,000,000
Common stock, shares, issued	193,642,000	194,408,000
Common stock, shares, outstanding	174,648,000	175,421,000
Treasury stock, shares	18,994,000	18,987,000