Condensed Consolidated Statements of Earnings and Comprehensive Earnings (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Condensed Consolidated Statements of Earnings and Comprehensive Earnings
Net premiums earned	$ 163,702	$ 149,943	$ 462,406	$ 428,807
Net investment income	13,598	14,221	39,331	44,340
Net realized investment gains	10,999	5,481	18,425	17,389
Other-than-temporary impairment (OTTI) losses on investments				(1,156)
Consolidated revenue	188,299	169,645	520,162	489,380
Losses and settlement expenses	64,246	70,598	191,301	193,486
Policy acquisition costs	54,176	49,262	156,014	145,632
Insurance operating expenses	13,462	11,553	37,916	34,595
Interest expense on debt	1,513	1,512	4,538	4,537
General corporate expenses	2,157	2,099	6,235	5,901
Total expenses	135,554	135,024	396,004	384,151
Equity in earnings of unconsolidated investee	2,564	1,859	10,696	8,928
Earnings before income taxes	55,309	36,480	134,854	114,157
Income tax expense	17,662	11,017	42,458	35,908
Net earnings	37,647	25,463	92,396	78,249
Other comprehensive earnings (loss), net of tax	(1,946)	21,047	(17,874)	37,713
Comprehensive earnings	$ 35,701	$ 46,510	$ 74,522	$ 115,962
Basic:
Basic net earnings per share (in dollars per share)	$ 1.76	$ 1.20	$ 4.33	$ 3.69
Basic comprehensive earnings per share (in dollars per share)	$ 1.67	$ 2.19	$ 3.49	$ 5.47
Diluted:
Diluted net earnings per share (in dollars per share)	$ 1.73	$ 1.19	$ 4.26	$ 3.64
Diluted comprehensive earnings per share (in dollars per share)	$ 1.64	$ 2.16	$ 3.44	$ 5.39
Weighted average number of common shares outstanding
Basic (in shares)	21,422	21,218	21,337	21,207
Diluted (in shares)	21,773	21,486	21,665	21,519
Cash dividends declared per common share (in dollars per share)	$ 0.34	$ 0.32	$ 1.00	$ 0.94