CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Premiums written:
Direct	$ 1,121,776	$ 1,107,923	$ 1,074,490
Assumed	1,905	1,053	1,178
Ceded	(125,726)	(133,885)	(55,391)
Net premiums written	997,955	975,091	1,020,277
Increase in unearned premiums	(63,208)	(49,865)	(124,055)
Net premiums earned	934,747	925,226	896,222
Investment income, net of expenses	120,871	110,666	103,741
Net realized investment gains	249	8,932	28,361
Other revenue	10,187	17,659	12,964
Total revenues	1,066,054	1,062,483	1,041,288
Losses and expenses:
Losses incurred, net	53,709	240,157	343,547
Change in premium deficiency reserve	0	0	(23,751)
Amortization of deferred policy acquisition costs	11,111	9,646	8,789
Other underwriting and operating expenses, net	159,638	150,763	155,577
Interest expense	57,035	56,672	68,932
Loss on debt extinguishment	65	90,531	507
Total losses and expenses	281,558	547,769	553,601
Income before tax	784,496	514,714	487,687
Provision for (benefit from) income taxes	428,735	172,197	(684,313)
Net income	$ 355,761	$ 342,517	$ 1,172,000
Earnings per share:
Basic (in dollars per share)	$ 0.98	$ 1.00	$ 3.45
Diluted (in dollars per share)	$ 0.95	$ 0.86	$ 2.60
Weighted average common shares outstanding - basic (in shares)	362,380	342,890	339,552
Weighted average common shares outstanding - diluted (in shares)	394,766	431,992	468,039
Dividends per share (in dollars per share)	$ 0	$ 0	$ 0