Consolidated Statements of Income and Comprehensive Income (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues
Net premiums earned	$ 194,219	$ 176,531	$ 557,403	$ 508,124
Investment income, net of investment expenses	27,278	28,665	82,761	86,560
Net realized investment gains (losses)
Other-than-temporary impairment charges	(139)	0	(139)	(4)
All other net realized gains (includes reclassifications for net unrealized gains on available-for-sale securities of $617 and $6,270 in 2013; and $91 and $3,111 in 2012; previously included in accumulated other comprehensive income)	1,329	1,300	7,389	4,662
Total net realized investment gains	1,190	1,300	7,250	4,658
Other income	337	85	634	584
Total revenues	223,024	206,581	648,048	599,926
Benefits, Losses and Expenses
Losses and loss settlement expenses	131,168	119,756	349,073	318,006
Increase in liability for future policy benefits	8,415	9,815	26,520	28,309
Amortization of deferred policy acquisition costs	38,767	36,167	113,556	104,897
Other underwriting expenses (includes reclassifications for employee benefit costs of $1,915 and $4,400 in 2013; and $1,085 and $3,460 in 2012; previously included in accumulated other comprehensive income)	21,654	20,496	67,310	63,031
Interest on policyholders’ accounts	8,625	10,327	27,026	31,610
Total benefits, losses and expenses	208,629	196,561	583,485	545,853
Income before income taxes	14,395	10,020	64,563	54,073
Federal income tax expense (includes reclassifications of $455 and ($654) in 2013; and $348 and $124 in 2012; previously included in accumulated other comprehensive income)	2,670	1,290	14,949	11,443
Net income	11,725	8,730	49,614	42,630
Other comprehensive income (loss)
Change in net unrealized appreciation on investments	(282)	19,404	(37,576)	41,335
Change in liability for underfunded employee benefit plans	0	0	0	0
Other comprehensive income (loss), before tax and reclassification adjustments	(282)	19,404	(37,576)	41,335
Income tax effect	107	(6,616)	13,152	(14,290)
Other comprehensive income (loss), after tax, before reclassification adjustments	(175)	12,788	(24,424)	27,045
Reclassification adjustment for net realized gains included in income	(617)	(91)	(6,270)	(3,111)
Reclassification adjustment for employee benefit costs included in expense	1,915	1,085	4,400	3,460
Total reclassification adjustments, before tax	1,298	994	(1,870)	349
Income tax effect	(455)	(348)	654	(124)
Total reclassification adjustments, after tax	843	646	(1,216)	225
Comprehensive income	$ 12,393	$ 22,164	$ 23,974	$ 69,900
Weighted average common shares outstanding (in shares)	25,359,196	25,423,191	25,301,432	25,468,293
Basic earnings per common share (in dollars per share)	$ 0.46	$ 0.34	$ 1.96	$ 1.67
Diluted earnings per common share (in dollars per share)	$ 0.45	$ 0.34	$ 1.94	$ 1.67
Cash dividends declared per common share (in dollars per share)	$ 0.18	$ 0.15	$ 0.51	$ 0.45