Consolidated Statements of Changes in Shareholders' Equity (unaudited) (USD $) In Thousands, except Share data	Total	Common Stock	Capital Surplus	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Deferred Benefits for Directors
Beginning Balance at Dec. 31, 2011	$ 633,790	$ 55,487	$ 191,679	$ 388,818	$ (96)	$ (902)	$ (1,196)
Beginning Balance, shares at Dec. 31, 2011		26,629,360
Net income	11,990			11,990
Other comprehensive income	576					576
Comprehensive income	12,566
Common dividends declared ($0.19 and $0.17 per share in March 31, 2013 and 2012 respectively)	(4,527)			(4,527)
Treasury shares acquired	(9)		22		(31)
Treasury shares acquired, shares		(1,671)
Stock compensation expense	181		181
Deferred benefits for directors - net			9				(9)
Ending Balance at Mar. 31, 2012	642,001	55,487	191,891	396,281	(127)	(326)	(1,205)
Ending Balance, shares at Mar. 31, 2012		26,627,689
Beginning Balance at Dec. 31, 2012	714,184	60,863	241,672	419,246		(6,365)	(1,232)
Beginning Balance, shares at Dec. 31, 2012		29,214,660
Net income	16,021			16,021
Other comprehensive income	(441)					(441)
Comprehensive income	15,580
Common dividends declared ($0.19 and $0.17 per share in March 31, 2013 and 2012 respectively)	(5,552)			(5,552)
Treasury shares acquired	(14)				(14)
Treasury shares acquired, shares		(620)
Stock options exercised	98	8	76		14
Stock options exercised, shares		4,650
Adjustment to shares issued in acquisition	(104)	(9)	(95)
Adjustment to shares issued in acquisition, shares		(4,672)
Stock compensation expense	217		217
Deferred benefits for directors - net			10				(10)
Ending Balance at Mar. 31, 2013	$ 724,409	$ 60,862	$ 241,880	$ 429,715		$ (6,806)	$ (1,242)
Ending Balance, shares at Mar. 31, 2013		29,214,018