Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues
Net premiums earned (Note 8)	$ 919,578	$ 981,131	$ 1,037,183
Services revenue (Note 4)	46,092	92,216	125,825
Net investment income (Note 6)	258,430	195,658	147,909
Net gains (losses) on investments and other financial instruments (includes net realized gains (losses) on investments of $(10,733), $(8,306) and $20,842) (Note 6)	10,241	(80,733)	15,603
Other income	6,247	2,454	3,412
Total revenues	1,240,588	1,190,726	1,329,932
Expenses
Provision for losses	(42,526)	(338,239)	20,877
Policy acquisition costs	24,578	23,918	29,029
Cost of services	38,491	82,358	103,714
Other operating expenses	347,578	381,148	323,686
Interest expense	89,695	84,454	84,344
Impairment of goodwill (Note 2)	9,802	0	0
Amortization of other acquired intangible assets	5,483	4,308	3,450
Total expenses	473,101	237,947	565,100
Pretax income	767,487	952,779	764,832
Income tax provision (Note 10)	164,368	209,845	164,161
Net income	$ 603,119	$ 742,934	$ 600,671
Net income per share
Basic (in usd per share)	$ 3.81	$ 4.42	$ 3.19
Diluted (in usd per share)	$ 3.77	$ 4.35	$ 3.16
Weighted-average number of common shares outstanding—basic (in shares)	158,140	167,930	188,370
Weighted-average number of common and common equivalent shares outstanding—diluted (in shares)	160,133	170,664	190,263