Consolidated Statements of Earnings and Comprehensive Earnings - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Consolidated Statements of Earnings and Comprehensive Earnings
Net premiums earned	$ 700,161	$ 687,375	$ 630,802
Net investment income	54,644	55,608	52,763
Net realized gains	39,829	32,182	22,036
Consolidated revenue	794,634	775,165	705,601
Losses and settlement expenses	299,045	296,609	259,801
Policy acquisition costs	241,078	229,283	210,651
Insurance operating expenses	51,480	54,464	53,557
Interest expense on debt	7,426	7,438	8,095
General corporate expenses	9,837	10,222	8,746
Total expenses	608,866	598,016	540,850
Equity in earnings of unconsolidated investees	10,914	12,338	10,915
Earnings before income taxes	196,682	189,487	175,666
Income tax expense:
Current	52,104	48,596	43,346
Deferred	7,034	5,446	6,065
Total tax expense	59,138	54,042	49,411
Net earnings	137,544	135,445	126,255
Other comprehensive earnings (loss), net of tax	(47,609)	35,356	(7,143)
Comprehensive earnings	$ 89,935	$ 170,801	$ 119,112
Basic:
Net earnings per share (in dollars per share)	$ 3.18	$ 3.15	$ 2.95
Comprehensive earnings per share (in dollars per share)	2.08	3.97	2.79
Diluted:
Net earnings per share (in dollars per share)	3.12	3.09	2.90
Comprehensive earnings per share (in dollars per share)	$ 2.04	$ 3.90	$ 2.74
Weighted average number of common shares outstanding
Basic (in shares)	43,299	43,020	42,744
Diluted (in shares)	44,131	43,819	43,514