Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Fixed maturity securities, amortized cost	$ 18,715,483	$ 16,471,304
Fixed maturity securities, allowance for credit loss	37,466	22,625
Financing receivable, allowance for credit loss	1,791	1,718
Premium receivable, allowance for credit loss	30,660	25,218
Uncollectible reinsurance	$ 8,064	$ 7,713
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, authorized (in shares)	5,000,000	5,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.20	$ 0.20
Common stock, issued (in shares)	264,546,100	265,170,882
Common stock, outstanding (in shares)	264,546,100	265,170,882
Common stock, authorized (in shares)	1,250,000,000	750,000,000
Treasury stock, at cost (in shares)	264,468,528	263,843,868