Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019		Sep. 30, 2018
Revenues:
Net premiums earned—insurance	$ 281,185	$ 258,431	$ 843,863	[1]	$ 752,325
Services revenue	42,509	36,566	114,565		106,558
Net investment income	42,756	38,995	130,364		110,424
Net gains (losses) on investments and other financial instruments	13,009	(4,480)	47,462		(30,771)
Other income	879	1,174	2,677		2,997
Total revenues	380,338	330,686	1,138,931		941,533
Expenses:
Provision for losses	29,231	20,881	97,412		77,501
Policy acquisition costs	6,435	5,667	18,531		18,780
Cost of services	29,044	25,854	81,046		73,185
Other operating expenses	76,384	70,125	225,235		203,552
Restructuring and other exit costs	0	4,464	0		5,940
Interest expense	13,492	15,535	44,150		45,906
Loss on extinguishment of debt	5,940	0	22,738		0
Amortization and impairment of other acquired intangible assets	2,139	3,472	6,465		8,968
Total expenses	162,665	145,998	495,577		433,832
Consolidated pretax income (loss)	217,673	184,688	643,354		507,701
Income tax provision	44,235	41,891	132,229		41,469
Net income	$ 173,438	$ 142,797	$ 511,125		$ 466,232
Earnings Per Share, Basic [Abstract]
Basic net income (loss) per share	$ 0.85	$ 0.67	$ 2.45		$ 2.17
Earnings Per Share, Diluted [Abstract]
Diluted net income (loss) per share	$ 0.83	$ 0.66	$ 2.39		$ 2.13
Weighted-average number of common shares outstanding—basic	203,107	213,309	208,561		214,499
Weighted-average number of common and common equivalent shares outstanding—diluted	208,691	217,902	213,963		218,783

[1] Includes a cumulative adjustment to unearned premiums recorded in the second quarter of 2019 related to an update to the amortization rates used to recognize revenue for Single Premium Policies. See Note 3 for further information.