Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues:
Net premiums earned—insurance	$ 263,512	$ 242,550
Services revenue	32,753	33,164
Net investment income	43,847	33,956
Net gains (losses) on investments and other financial instruments	21,913	(18,887)
Other income	1,604	807
Total revenues	363,629	291,590
Expenses:
Provision for losses	20,754	37,283
Policy acquisition costs	5,893	7,117
Cost of services	24,157	23,126
Other operating expenses	78,805	63,243
Restructuring and other exit costs (Note 1)	0	551
Interest expense	15,697	15,080
Amortization and impairment of other acquired intangible assets	2,187	2,748
Total expenses	147,493	149,148
Consolidated pretax income (loss)	216,136	142,442
Income tax provision	45,179	27,956
Net income	$ 170,957	$ 114,486
Earnings Per Share, Basic [Abstract]
Basic net income (loss) per share	$ 0.80	$ 0.53
Earnings Per Share, Diluted [Abstract]
Diluted net income (loss) per share	$ 0.78	$ 0.52
Weighted-average number of common shares outstanding—basic	213,537	215,967
Weighted-average number of common and common equivalent shares outstanding—diluted	218,343	219,883