CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Common Stock [Member]	Surplus [Member]	Comprehensive Income [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2008	$ 719	$ 1,354		$ 102,061	$ (1,602)	$ 102,532
Balance (in shares) at Dec. 31, 2008	7,194,747
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income			13,463	13,463		13,463
Other comprehensive income (loss),net of tax and reclassification adjustment			5,253		5,253	5,253
Comprehensive income			18,716
Repurchase of common stock	(4)	(953)				(957)
Repurchase of common stock (in shares)	(37,443)
Common stock issued under stock compensation plans,including tax benefit	6	961				967
Common stock issued under stock compensation plans,including tax benefit (in shares)	55,752
Stock-based compensation		681				681
Cash dividends declared				(5,477)		(5,477)
Balance at Dec. 31, 2009	721	2,043		110,047	3,651	116,462
Balance (in shares) at Dec. 31, 2009	7,213,056
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income			18,392	18,392		18,392
Other comprehensive income (loss),net of tax and reclassification adjustment			(5,067)		(5,067)	(5,067)
Comprehensive income			13,325
Repurchase of common stock	0	(91)				(91)
Repurchase of common stock (in shares)	(3,581)
Common stock issued under stock compensation plans,including tax benefit	6	709				715
Common stock issued under stock compensation plans,including tax benefit (in shares)	60,690
Issuance of common stock	144	32,218				32,362
Issuance of common stock (in shares)	1,437,500
Stock-based compensation		647				647
Cash dividends declared				(6,726)		(6,726)
Balance at Dec. 31, 2010	871	35,526		121,713	(1,416)	156,694
Balance (in shares) at Dec. 31, 2010	8,707,665
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income			19,457	19,457		19,457
Other comprehensive income (loss),net of tax and reclassification adjustment			19,104		19,104	19,104
Comprehensive income			38,561
Repurchase of common stock	(1)	(184)				(185)
Repurchase of common stock (in shares)	(7,022)
Common stock issued under stock compensation plans,including tax benefit	9	1,409				1,418
Common stock issued under stock compensation plans,including tax benefit (in shares)	93,289
Stock-based compensation		756				756
Cash dividends declared				(7,897)		(7,897)
Balance at Dec. 31, 2011	$ 879	$ 37,507		$ 133,273	$ 17,688	$ 189,347
Balance (in shares) at Dec. 31, 2011	8,793,932