Consolidated Statements of Income (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Gross written premiums	$ 1,370,517	$ 1,286,465	$ 1,108,216
Revenues:
Net written premiums	887,922	833,655	753,798
Change in unearned premiums	(45,983)	(51,691)	(62,153)
Net earned premiums	841,939	781,964	691,645
Net investment income	56,251	54,248	63,500
Total other-than-temporary impairment losses	(2,393)	(902)	(3,617)
Portion of loss recognized in other comprehensive income (before tax)		44	1,632
Net other-than-temporary impairment losses recognized in earnings	(2,393)	(858)	(1,985)
Net realized gains (losses)	22,939	41,074	11,996
Other income (expense)	(1,172)	1,488	1,229
Total revenues	917,564	877,916	766,385
Expenses:
Net losses and loss adjustment expenses	518,961	497,433	476,997
Commission expenses	113,494	121,470	110,437
Other operating expenses	164,434	159,079	138,029
Call premium on Senior Notes	17,895
Interest expense	10,507	8,198	8,188
Total expenses	825,291	786,180	733,651
Income before income taxes	92,273	91,736	32,734
Income tax expense (benefit)	28,807	27,974	7,137
Net income	$ 63,466	$ 63,762	$ 25,597
Net income per common share:
Basic	$ 4.49	$ 4.54	$ 1.71
Diluted	$ 4.42	$ 4.45	$ 1.69
Average common shares outstanding:
Basic	14,133,925	14,052,311	14,980,429
Diluted	14,345,553	14,327,820	15,183,285