Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Fixed maturities available for sale, allowance for credit loss	$ 0	$ (948)
Total fixed-maturities available for sale	5,367,729	5,393,623
Trading securities, amortized cost	234,382	260,773
Equity securities, amortized cost	176,229	145,501
Reinvested cash collateral held under securities lending agreements	48,652	15,587
Reinsurance recoverables, paid losses	$ 51	$ 32
Common stock, par value (usd per share)	$ 0.001
Common stock, shares authorized (in shares)	485,000,000	485,000,000
Common stock, shares, issued (in shares)	194,408,000	210,130,000
Common stock, shares, outstanding (in shares)	175,421,000	191,606,000
Treasury stock (in shares)	18,987,000	18,524,000