Consolidated Statements of Changes in Shareholders' Equity (Unaudited) (USD $) In Thousands, except Share data	Total USD ($)		Common Shares Outstanding	Accumulated Other Comprehensive (Loss) Income USD ($)	Common Stock USD ($)	Additional Paid-in Capital USD ($)	Retained Earnings USD ($)	Treasury Stock USD ($)
Beginning balance at Dec. 31, 2010	$ 266,224			$ (6,766)	$ 91,332	$ 59,080	$ 151,978	$ (29,400)
Beginning balance, shares at Dec. 31, 2010			16,648,303
Net income	8,378						8,378
Other comprehensive income, net of taxes	3,667			3,667
Cash dividends declared ($0.40 per share)	(6,688)						(6,688)
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs	1,290					62	13	1,215
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs, shares			73,345
Purchases of treasury stock, shares			(3,005)
Purchases of treasury stock	(52)							(52)
Restricted stock awards granted, shares			58,736
Restricted stock awards granted						(1,019)	47	972
Vesting of restricted stock awards	203					203
Ending balance at Jun. 30, 2011	273,022			(3,099)	91,332	58,326	153,728	(27,265)
Ending balance, shares at Jun. 30, 2011			16,777,379
Beginning balance at Dec. 31, 2011	272,979	[1]		(6,101)	91,332	58,495	157,566	(28,313)
Beginning balance, shares at Dec. 31, 2011			16,702,376
Net income	10,026						10,026
Other comprehensive income, net of taxes	206			206
Cash dividends declared ($0.40 per share)	(6,706)						(6,706)
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs	1,461						(65)	1,526
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs, shares			90,339
Cancelled stock options and awards, shares			(13,125)
Cancelled stock options and awards	33					300	(54)	(213)
Tax expense on stock based compensation	(84)					(84)
Purchases of treasury stock, shares			(90,854)
Purchases of treasury stock	(1,446)							(1,446)
Restricted stock awards granted, shares			71,157
Restricted stock awards granted						(1,154)	(134)	1,288
Vesting of restricted stock awards	847					847
Ending balance at Jun. 30, 2012	$ 277,316			$ (5,895)	$ 91,332	$ 58,404	$ 160,633	$ (27,158)
Ending balance, shares at Jun. 30, 2012			16,759,893

[1] Note: The consolidated balance sheet at December 31, 2011 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by U. S. generally accepted accounting principles for complete financial statements. Certain amounts have been reclassified to conform to the current-year presentation. See accompanying notes to the unaudited consolidated financial statements.