Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues:
Net premiums earned—insurance	$ 258,431	$ 236,702	$ 752,325	$ 687,598
Services revenue	36,566	39,571	106,558	115,400
Net investment income	38,995	32,540	110,424	93,643
Net gains (losses) on investments and other financial instruments	(4,480)	2,480	(30,771)	4,960
Other income	1,174	760	2,997	2,118
Total revenues	330,686	312,053	941,533	903,719
Expenses:
Provision for losses	20,881	35,841	77,501	99,976
Policy acquisition costs	5,667	5,554	18,780	18,406
Cost of services	25,854	27,240	73,185	81,250
Other operating expenses	70,125	64,195	203,552	201,322
Restructuring and other exit costs (Note 1)	4,464	12,038	5,940	12,038
Interest expense	15,535	15,715	45,906	47,832
Loss on induced conversion and debt extinguishment	0	45,766	0	51,469
Impairment of goodwill (Note 6)	0	0	0	184,374
Amortization and impairment of other acquired intangible assets	3,472	2,890	8,968	25,042
Total expenses	145,998	209,239	433,832	721,709
Consolidated pretax income (loss)	184,688	102,814	507,701	182,010
Income tax provision	41,891	37,672	41,469	67,738
Net income	$ 142,797	$ 65,142	$ 466,232	$ 114,272
Earnings Per Share, Basic [Abstract]
Basic net income (loss) per share	$ 0.67	$ 0.30	$ 2.17	$ 0.53
Earnings Per Share, Diluted [Abstract]
Diluted net income (loss) per share	$ 0.66	$ 0.30	$ 2.13	$ 0.52
Weighted-average number of common shares outstanding—basic	213,309	215,279	214,499	215,194
Weighted-average number of common and common equivalent shares outstanding—diluted	217,902	219,391	218,783	220,230