Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenues
Net premiums earned	$ 186,367	$ 170,090	$ 363,184	$ 331,593
Investment income, net of investment expenses	29,019	28,749	55,483	57,895
Net realized investment gains
Other-than-temporary impairment charges	0	(4)	0	(4)
All other net realized gains (includes reclassifications for net unrealized gains on available-for-sale securities of $4,417 and $5,653 in 2013; and $788 and $3,020 in 2012; previously included in accumulated other comprehensive income)	4,151	568	6,060	3,362
Total net realized investment gains	4,151	564	6,060	3,358
Other income	182	243	297	499
Total revenues	219,719	199,646	425,024	393,345
Benefits, Losses and Expenses
Losses and loss settlement expenses	120,435	106,766	217,905	198,250
Future policy benefits	9,869	8,356	18,105	18,494
Amortization of deferred policy acquisition costs	36,708	34,179	74,789	68,730
Other underwriting expenses (includes reclassifications for employee benefit costs of $1,243 and $2,485 in 2013; and $1,732 and $2,375 in 2012; previously included in accumulated other comprehensive income)	23,308	20,541	45,656	42,535
Interest on policyholders’ accounts	9,081	10,627	18,401	21,283
Total benefits, losses and expenses	199,401	180,469	374,856	349,292
Income before income taxes	20,318	19,177	50,168	44,053
Federal income tax expense (includes reclassifications of $1,111 and $1,109 in 2013; and ($331) and $224 in 2012; previously included in accumulated other comprehensive income)	4,822	4,461	12,279	10,153
Net income	15,496	14,716	37,889	33,900
Other comprehensive income (loss)
Change in net unrealized appreciation on investments	(51,782)	8,891	(37,294)	21,932
Change in liability for underfunded employee benefit plans	0	0	0	0
Other comprehensive income (loss), before tax and reclassification adjustments	(51,782)	8,891	(37,294)	21,932
Income tax effect	18,115	(3,111)	13,045	(7,675)
Other comprehensive income (loss), after tax, before reclassification adjustments	(33,667)	5,780	(24,249)	14,257
Reclassification adjustment for net realized gains included in income	(4,417)	(788)	(5,653)	(3,020)
Reclassification adjustment for employee benefit costs included in expense	1,243	1,732	2,485	2,375
Total reclassification adjustments, before tax	(3,174)	944	(3,168)	(645)
Income tax effect	1,111	(331)	1,109	224
Total reclassification adjustments, after tax	(2,063)	613	(2,059)	(421)
Comprehensive income (loss)	$ (20,234)	$ 21,109	$ 11,581	$ 47,736
Weighted average common shares outstanding (in shares)	25,297,718	25,476,220	25,271,752	25,491,091
Basic earnings per common share (in dollars per share)	$ 0.61	$ 0.58	$ 1.50	$ 1.33
Diluted earnings per common share (in dollars per share)	$ 0.61	$ 0.58	$ 1.49	$ 1.33
Cash dividends declared per common share (in dollars per share)	$ 0.18	$ 0.15	$ 0.33	$ 0.3