Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues
Net premiums earned	$ 368,704	$ 375,894	$ 375,747
Net investment income	28,106	27,902	27,214
Net realized gains (losses) on investments	(494)	(2,494)	697
Loss on disposal of assets	(1)	(664)
Fee and other income	347	316	361
Total revenues	396,662	400,954	404,019
Expenses
Loss and loss adjustment expenses incurred	199,031	214,573	244,916
Underwriting and certain other operating costs	29,470	32,162	32,573
Commissions	26,243	27,509	27,872
Salaries and benefits	24,881	24,442	24,518
Policyholder dividends	4,216	1,301	391
Total expenses	283,841	299,987	330,270
Income before income taxes	112,821	100,967	73,749
Income tax expense	34,956	30,505	20,083
Net income	77,865	70,462	53,666
Net income available to common shareholders	$ 77,865	$ 70,462	$ 53,666
Earnings per share
Basic	$ 4.08	$ 3.72	$ 2.88
Diluted	$ 4.05	$ 3.69	$ 2.84
Shares used in computing earnings per share
Basic	19,105,806	18,941,077	18,646,128
Diluted	19,203,650	19,119,186	18,928,504
Extraordinary cash dividends declared per common share	$ 3.25	$ 3.00	$ 1.50
Cash dividends declared per common share	$ 0.72	$ 0.60	$ 0.48