Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues
Premiums earned	$ 375,894	$ 375,747	$ 329,983
Net investment income	27,902	27,214	27,029
Net realized gains (losses) on investments	(2,494)	697	(1,211)
Loss on disposal of assets	(664)		(2)
Fee and other income	316	361	536
Total revenues	400,954	404,019	356,335
Expenses
Loss and loss adjustment expenses incurred	214,573	244,916	228,973
Underwriting and certain other operating costs	32,162	32,573	18,951
Commissions	27,509	27,872	25,303
Salaries and benefits	24,442	24,518	22,862
Policyholder dividends	1,301	391	1,042
Total expenses	299,987	330,270	297,131
Income before income taxes	100,967	73,749	59,204
Income tax expense	30,505	20,083	15,567
Net income	70,462	53,666	43,637
Net income available to common shareholders	$ 70,462	$ 53,666	$ 43,495
Earnings per share
Basic	$ 3.72	$ 2.88	$ 2.37
Diluted	$ 3.69	$ 2.84	$ 2.32
Shares used in computing earnings per share
Basic	18,941,077	18,646,128	18,373,033
Diluted	19,119,186	18,928,504	18,748,809
Extraordinary cash dividends declared per common share	$ 3.00	$ 1.50	$ 0.00
Cash dividends declared per common share	$ 0.60	$ 0.48	$ 0.32