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
Revenues
Premiums earned	$ 329,983	$ 290,689	$ 251,015
Net investment income	27,029	27,018	26,340
Net realized gains (losses) on investments	(1,211)	2,979	2,228
Fee and other income	534	562	1,080
Total revenues	356,335	321,248	280,663
Expenses
Loss and loss adjustment expenses incurred	228,973	219,903	189,706
Underwriting and certain other operating costs	18,951	18,450	22,404
Commissions	25,303	22,144	18,507
Salaries and benefits	22,862	20,839	19,914
Interest expense		566	1,311
Policyholder dividends	1,042	2,203	1,464
Total expenses	297,131	284,105	253,306
Income before income taxes	59,204	37,143	27,357
Income tax expense	15,567	7,790	3,176
Net income	43,637	29,353	24,181
Net income available to common shareholders	$ 43,495	$ 29,331	$ 24,167
Earnings per share
Basic	$ 2.37	$ 1.62	$ 1.32
Diluted	$ 2.32	$ 1.58	$ 1.29
Shares used in computing earnings per share
Basic	18,373,033	18,166,261	18,249,583
Diluted	18,748,809	18,575,191	18,692,711
Cash dividends declared per common share	$ 0.32