Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Investments (Notes 5 and 6)
Fixed-maturities available for sale—at fair value (amortized cost of $5,683,372 and $5,587,261)	$ 5,037,747	$ 5,017,711
Trading securities—at fair value (amortized cost of $110,676 and $122,472)	99,769	115,665
Equity securities—at fair value (cost of $113,248 and $162,899)	108,911	148,965
Mortgage loans held for sale—at fair value	138,289	3,549
Other invested assets—at fair value	8,492	5,511
Short-term investments—at fair value (includes $119,197 and $99,735 of reinvested cash collateral held under securities lending agreements)	492,444	402,090
Total investments	5,885,652	5,693,491
Cash	55,489	56,183
Restricted cash	1,305	377
Accrued investment income	45,623	40,093
Accounts and notes receivable	144,614	119,834
Reinsurance recoverables (includes $68 and $18 for paid losses)	24,148	25,633
Deferred policy acquisition costs	18,817	18,460
Property and equipment, net	74,558	70,981
Goodwill and other acquired intangible assets, net (Note 7)	11,173	15,285
Prepaid federal income taxes (Note 10)	696,820	596,368
Other assets (Note 9)	420,483	427,024
Total assets	7,378,682	7,063,729
Liabilities
Unearned premiums	236,400	271,479
Reserve for losses and LAE (Note 11)	367,568	426,843
Senior notes (Note 12)	1,416,687	1,413,504
Secured borrowings (Note 12)	241,753	155,822
Reinsurance funds withheld	156,114	152,067
Net deferred tax liability	497,560	391,083
Other liabilities	309,701	333,604
Total liabilities	3,225,783	3,144,402
Commitments and contingencies (Note 13)
Stockholders’ equity
Common stock ($0.001 par value; 485,000 shares authorized; 2023: 175,636 and 155,582 shares issued and outstanding, respectively; 2022: 176,509 and 157,056 shares issued and outstanding, respectively)	175	176
Treasury stock, at cost (2023: 20,054 shares; 2022: 19,453 shares)	(945,504)	(930,643)
Additional paid-in capital	1,482,712	1,519,641
Retained earnings	4,136,598	3,786,952
Accumulated other comprehensive income (loss) (Note 15)	(521,082)	(456,799)
Total stockholders’ equity	4,152,899	3,919,327
Total liabilities and stockholders’ equity	$ 7,378,682	$ 7,063,729