Consolidated Statements of Changes in Shareholders' Equity (Unaudited) (USD $) In Thousands, except Share data	Total		Common Stock [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]
Beginning balance at Dec. 31, 2011	$ 272,979		$ 91,332	$ (6,101)	$ 58,495	$ 157,566	$ (28,313)
Beginning balance, shares at Dec. 31, 2011			16,702,376
Net income	15,796					15,796
Other comprehensive income (loss), net of income tax benefit	1,966			1,966
Cash dividends declared ($0.60 per share)	(10,058)					(10,058)
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs	1,987					(64)	2,051
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs, shares			121,012
Repurchase of cancelled restricted stock awards					300	(87)	(213)
Repurchase of cancelled restricted stock awards, shares			(13,125)
Stock-based compensation	880				847	33
Net tax deficiency on stock-based compensation	(84)				(84)
Purchases of treasury stock	(1,877)						(1,877)
Purchases of treasury stock, shares			(116,294)
Restricted stock awards granted					(1,154)	(134)	1,288
Restricted stock awards granted, shares			71,157
Ending balance at Sep. 30, 2012	281,589		91,332	(4,135)	58,404	163,052	(27,064)
Ending balance, shares at Sep. 30, 2012			16,765,126
Beginning balance at Dec. 31, 2012	284,277	[1]	91,332	(6,920)	62,101	164,823	(27,059)
Beginning balance, shares at Dec. 31, 2012			16,770,232
Net income	16,267					16,267
Other comprehensive income (loss), net of income tax benefit	(6,783)			(6,783)
Cash dividends declared ($0.60 per share)	(10,029)					(10,029)
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs	1,892				9	(32)	1,915
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs, shares			105,263
Repurchase of cancelled restricted stock awards					519		(519)
Repurchase of cancelled restricted stock awards, shares			(29,533)
Stock-based compensation	616				616
Net tax deficiency on stock-based compensation	(11)				(11)
Purchases of treasury stock	(11,475)						(11,475)
Purchases of treasury stock, shares			(627,406)
Restricted stock awards granted					(1,174)	(92)	1,266
Restricted stock awards granted, shares			70,041
Ending balance at Sep. 30, 2013	$ 274,754		$ 91,332	$ (13,703)	$ 62,060	$ 170,937	$ (35,872)
Ending balance, shares at Sep. 30, 2013			16,288,597

[1] Note: The consolidated balance sheet at December 31, 2012 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. See accompanying notes to the unaudited consolidated financial statements.