Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues
Net premiums earned (Note 8)	$ 254,756	$ 249,295	$ 526,628	$ 526,710
Services revenue (Note 4)	29,464	28,075	52,359	60,002
Net investment income	36,291	38,723	74,542	79,667
Net gains (losses) on investments and other financial instruments	15,661	47,276	10,480	25,249
Other income	822	1,072	1,798	1,894
Total revenues	336,994	364,441	665,807	693,522
Expenses
Provision for losses	3,648	304,418	49,791	340,369
Policy acquisition costs	4,838	6,015	13,834	13,428
Cost of Services	24,615	17,972	44,861	40,113
Other operating expenses	86,469	60,582	156,731	129,692
Interest expense	21,065	16,699	42,180	28,893
Amortization and impairment of other acquired intangible assets	863	979	1,725	1,958
Total expenses	141,498	406,665	309,122	554,453
Consolidated pretax income (loss)	195,496	(42,224)	356,685	139,069
Income tax provision (benefit)	40,290	(12,273)	75,871	28,559
Net income (loss)	$ 155,206	$ (29,951)	$ 280,814	$ 110,510
Earnings Per Share, Basic [Abstract]
Basic net income (loss) per share	$ 0.80	$ (0.15)	$ 1.45	$ 0.56
Earnings Per Share, Diluted [Abstract]
Diluted net income (loss) per share	$ 0.80	$ (0.15)	$ 1.44	$ 0.56
Weighted-average number of common shares outstanding—basic	193,436	193,299	193,692	197,545
Weighted-average number of common and common equivalent shares outstanding—diluted	194,638	193,299	194,986	198,746