Consolidated Statements of Income (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Gross written premiums	$ 422,790	$ 393,222
Revenues:
Net written premiums	311,850	269,452
Change in unearned premiums	(86,578)	(67,124)
Net earned premiums	225,272	202,328
Net investment income	16,610	13,657
Total other-than-temporary impairment losses		(42)
Portion of loss recognized in other comprehensive income (before tax)
Net other-than-temporary impairment losses recognized in earnings		(42)
Net realized gains (losses)	833	4,814
Other income (expense)	10,399	618
Total revenues	253,114	221,375
Expenses:
Net losses and loss adjustment expenses	135,067	131,342
Commission expenses	25,727	26,555
Other operating expenses	47,146	40,874
Interest expense	3,852	2,051
Total expenses	211,792	200,822
Income (loss) before income taxes	41,322	20,553
Income tax expense (benefit)	13,354	6,643
Net income	$ 27,968	$ 13,910
Net income per common share:
Basic	$ 1.96	$ 0.99
Diluted	$ 1.94	$ 0.97
Average common shares outstanding:
Basic	14,233,504	14,085,821
Diluted	14,408,416	14,374,957