Condensed Consolidated Statements of Changes in Shareholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Preferred Stock	Common Stock	Surplus	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Comprehensive Income
Balance at Dec. 31, 2011	$ 381,780		$ 35,099	$ 233,232	$ 116,198	$ (2,749)
Balance (in shares) at Dec. 31, 2011			14,039,422
Comprehensive income (loss):
Net income	7,028				7,028		7,028
Other comprehensive loss, net of tax	(133)					(133)	(133)
Comprehensive income	6,895						6,895
Cash dividends declared at $.18 and $.17 per share for the period ended 31st March, 2013 and 2012 respectively	(2,389)				(2,389)
Stock options exercised	12		1	11
Stock options exercised (in shares)			606
Restricted stock awards			48	(48)
Restricted stock awards (in shares)			19,314
Common stock repurchased	(219)		(18)	(201)
Common stock repurchased (in shares)			(7,165)
Share-based compensation expense	428			428
Balance at Mar. 31, 2012	386,507		35,130	233,422	120,837	(2,882)
Balance (in shares) at Mar. 31, 2012	14,052,177		14,052,177
Balance at Dec. 31, 2012	507,549		42,344	328,843	135,986	376
Balance (in shares) at Dec. 31, 2012	16,937,464		16,937,464
Comprehensive income (loss):
Net income	10,649				10,649		10,649
Other comprehensive loss, net of tax	(1,919)					(1,919)	(1,919)
Comprehensive income	8,730						8,730
Cash dividends declared at $.18 and $.17 per share for the period ended 31st March, 2013 and 2012 respectively	(3,062)				(3,062)
Stock options exercised	516		45	471
Stock options exercised (in shares)			18,211
Restricted stock awards			171	(171)
Restricted stock awards (in shares)			68,308
Common stock repurchased	(305)		(15)	(290)
Common stock repurchased (in shares)			(6,079)
Share-based compensation expense	783			783
Balance at Mar. 31, 2013	$ 514,211	$ 0	$ 42,545	$ 329,636	$ 143,573	$ (1,543)
Balance (in shares) at Mar. 31, 2013	17,017,904	0	17,017,904