Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenues
Net premiums earned (Note 8)	$ 981,131	$ 1,037,183	$ 1,115,321
Services revenue (Note 4)	92,216	125,825	105,385
Net investment income (Note 6)	195,658	147,909	154,037
Net gains (losses) on investments and other financial instruments (includes net realized gains (losses) on investments of $(8,278), $20,842 and $35,826) (Note 6)	(80,733)	15,603	60,277
Other income	2,454	3,412	3,597
Total revenues	1,190,726	1,329,932	1,438,617
Expenses
Provision for losses	(338,239)	20,877	485,117
Policy acquisition costs	23,918	29,029	30,989
Cost of services	82,358	103,714	86,066
Other operating expenses	381,148	323,686	280,710
Interest expense	84,454	84,344	71,150
Amortization of other acquired intangible assets	4,308	3,450	5,144
Total expenses	237,947	565,100	959,176
Pretax income	952,779	764,832	479,441
Income tax provision (Note 10)	209,845	164,161	85,815
Net income	$ 742,934	$ 600,671	$ 393,626
Net income per share
Net income per share, basic (in usd per share)	$ 4.42	$ 3.19	$ 2.01
Net income per share, diluted (in usd per share)	$ 4.35	$ 3.16	$ 2.00
Weighted-average number of common shares outstanding—basic (in shares)	167,930	188,370	195,443
Weighted-average number of common and common equivalent shares outstanding—diluted (in shares)	170,664	190,263	196,642