Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues
Net earned premiums	$ 755,760	$ 738,164	$ 716,875
Net investment income	38,413	40,534	42,303
Earnings from partnership investments	3,185	2,387	878
Net realized gains (losses) on investments	5,559	(469)	197
Net impairment losses on investments	(798)	(796)
Finance and other service income	17,703	18,133	18,544
Total revenue	819,822	797,953	778,797
Expenses
Losses and loss adjustment expenses	493,433	612,569	476,366
Underwriting, operating and related expenses	233,017	213,939	219,023
Interest expense	90	90	90
Total expenses	726,540	826,598	695,479
Income (loss) before income taxes	93,282	(28,645)	83,318
Income tax expense (credit)	28,697	(14,792)	23,964
Net income (loss)	$ 64,585	$ (13,853)	$ 59,354
Earnings (loss) per weighted average common share:
Basic (in dollars per share)	$ 4.29	$ (0.93)	$ 3.93
Diluted (in dollars per share)	4.27	(0.93)	3.91
Cash dividends paid per common share (in dollars per share)	$ 2.80	$ 2.80	$ 2.60
Number of shares used in computing earnings (loss) per share:
Basic (in shares)	14,946,453	14,866,607	14,963,047
Diluted (in shares)	15,032,263	14,866,607	15,052,745