Condensed Consolidated Statements of Earnings and Comprehensive Earnings (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Condensed Consolidated Statements of Earnings and Comprehensive Earnings
Net premiums earned	$ 154,553	$ 141,584	$ 298,704	$ 278,864
Net investment income	12,847	14,826	25,733	30,119
Net realized investment gains	3,742	492	7,426	11,908
Other-than-temporary impairment (OTTI) losses on investments		(1,156)		(1,156)
Consolidated revenue	171,142	155,746	331,863	319,735
Losses and settlement expenses	65,607	61,005	127,055	122,888
Policy acquisition costs	51,502	48,173	101,838	96,370
Insurance operating expenses	11,885	10,783	24,454	23,042
Interest expense on debt	1,513	1,525	3,025	3,025
General corporate expenses	1,692	1,815	4,078	3,802
Total expenses	132,199	123,301	260,450	249,127
Equity in earnings of unconsolidated investee	4,633	4,123	8,132	7,069
Earnings before income taxes	43,576	36,568	79,545	77,677
Income tax expense	13,674	11,820	24,796	24,891
Net earnings	29,902	24,748	54,749	52,786
Other comprehensive earnings (loss), net of tax	(33,481)	5,890	(15,928)	16,666
Comprehensive earnings (loss)	$ (3,579)	$ 30,638	$ 38,821	$ 69,452
Basic:
Basic net earnings per share (in dollars per share)	$ 1.40	$ 1.17	$ 2.57	$ 2.49
Basic comprehensive earnings (loss) per share (in dollars per share)	$ (0.17)	$ 1.44	$ 1.82	$ 3.28
Diluted:
Diluted net earnings per share (in dollars per share)	$ 1.38	$ 1.15	$ 2.53	$ 2.45
Diluted comprehensive earnings (loss) per share (in dollars per share)	$ (0.17)	$ 1.42	$ 1.79	$ 3.23
Weighted average number of common shares outstanding
Basic (in shares)	21,314	21,213	21,293	21,200
Diluted (in shares)	21,670	21,514	21,634	21,521
Cash dividends declared per common share (in dollars per share)	$ 0.34	$ 0.32	$ 0.66	$ 0.62