Consolidated Statements of Changes in Shareholders' Equity (Unaudited) (USD $) In Thousands	Capital Stock [Member]	Surplus [Member]	Undivided Profits [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2010	$ 83,166	$ 126,982	$ 108,780	$ (4,119)	$ (59,369)	$ 255,440
Net Income	0	0	24,373	0	0	24,373
Change in other comprehensive income, net of tax	0	0	0	4,377	0	4,377
Proceeds from stock offering (15,640,000 shares)	15,640	51,938	0	0	0	67,578
Cash dividend declared	0	0	(16,259)	0	0	(16,259)
Sale of treasury stock	0	(1,583)	0	0	3,773	2,190
Stock based compensation expense	0	111	0	0	0	111
Balance at Sep. 30, 2011	98,806	177,448	116,894	258	(55,596)	337,810
Balance at Dec. 31, 2011	98,912	176,638	119,465	(2,493)	(54,006)	338,516
Net Income	0	0	27,728	0	0	27,728
Change in other comprehensive income, net of tax	0	0	0	7,372	0	7,372
Cash dividend declared	0	0	(18,443)	0	0	(18,443)
Sale of treasury stock	0	(1,622)	0	0	3,798	2,176
Stock based compensation expense	0	268	0	0	0	268
Balance at Sep. 30, 2012	$ 98,912	$ 175,284	$ 128,750	$ 4,879	$ (50,208)	$ 357,617