CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Premiums written:
Direct	$ 1,124,196	$ 1,103,332	$ 1,121,776
Assumed	6,446	271	1,905
Ceded	(129,334)	(111,341)	(125,726)
Net premiums written	1,001,308	992,262	997,955
Decrease (increase) in unearned premiums	29,680	(17,100)	(63,208)
Net premiums earned	1,030,988	975,162	934,747
Investment income, net of expenses	167,045	141,331	120,871
Net realized investment gains (losses)	5,306	(1,353)	231
Other revenue	10,638	8,708	10,205
Total revenues	1,213,977	1,123,848	1,066,054
Losses and expenses:
Losses incurred, net	118,575	36,562	53,709
Amortization of deferred policy acquisition costs	12,001	11,932	11,111
Other underwriting and operating expenses, net	182,768	178,211	159,638
Interest expense	52,656	52,993	57,035
Loss on debt extinguishment	0	0	65
Total losses and expenses	366,000	279,698	281,558
Income before tax	847,977	844,150	784,496
Provision for income taxes	174,214	174,053	428,735
Net income	$ 673,763	$ 670,097	$ 355,761
Earnings per share:
Basic (in dollars per share)	$ 1.91	$ 1.83	$ 0.98
Diluted (in dollars per share)	$ 1.85	$ 1.78	$ 0.95
Weighted average common shares outstanding - basic (in shares)	352,827	365,406	362,380
Weighted average common shares outstanding - diluted (in shares)	373,924	386,078	394,766