Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues
Net premiums earned (Note 8)	$ 249,118	$ 286,471	$ 775,746	$ 813,181
Services revenue (Note 4)	37,773	33,943	90,132	93,945
Net investment income	35,960	36,255	110,502	115,922
Net gains (losses) on investments and other financial instruments	2,098	17,652	12,578	42,901
Other income	809	913	2,607	2,807
Total revenues	325,758	375,234	991,565	1,068,756
Expenses
Provision for losses	17,305	88,084	67,096	428,453
Policy acquisition costs	7,924	10,166	21,758	23,594
Cost of Services	30,520	24,353	75,381	64,466
Other operating expenses	86,479	69,377	243,210	199,069
Interest expense	21,027	21,088	63,207	49,981
Amortization and impairment of other acquired intangible assets	862	961	2,587	2,919
Total expenses	164,117	214,029	473,239	768,482
Consolidated pretax income (loss)	161,641	161,205	518,326	300,274
Income tax provision	35,229	26,102	111,100	54,661
Net income	$ 126,412	$ 135,103	$ 407,226	$ 245,613
Earnings Per Share, Basic [Abstract]
Basic net income (loss) per share	$ 0.68	$ 0.70	$ 2.13	$ 1.25
Earnings Per Share, Diluted [Abstract]
Diluted net income (loss) per share	$ 0.67	$ 0.70	$ 2.11	$ 1.25
Weighted-average number of common shares outstanding—basic	186,741	193,176	191,357	196,120
Weighted-average number of common and common equivalent shares outstanding—diluted	188,042	194,156	192,902	197,247