Consolidated Statements of Changes in Shareholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Treasury Stock [Member]
Beginning balance at Dec. 31, 2012	$ 284,277	$ 91,332	$ 62,101	$ 164,823	$ (6,920)	$ (27,059)
Beginning balance, shares at Dec. 31, 2012		16,770,232
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	16,267	0	0	16,267	0	0
Other comprehensive income (loss), net of income tax benefit	(6,783)	0	0	0	(6,783)	0
Cash dividends declared ($0.60 per share)	(10,029)	0	0	(10,029)	0	0
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs	1,892	0	9	(32)	0	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	0		519			(519)
Repurchase of cancelled restricted stock awards, shares		(29,533)
Stock-based compensation	616	0	616	0	0	0
Net tax deficiency on stock-based compensation	(11)	0	(11)	0	0	0
Purchases of treasury stock	(11,475)	0	0	0	0	(11,475)
Purchases of treasury stock, shares		(627,406)
Restricted stock awards granted	0	0	(1,174)	(92)	0	1,266
Restricted stock awards granted, shares		70,041
Ending balance at Sep. 30, 2013	274,754	91,332	62,060	170,937	(13,703)	(35,872)
Ending balance, shares at Sep. 30, 2013		16,288,597
Beginning balance at Dec. 31, 2013	280,506	91,332	62,417	172,602	(9,955)	(35,890)
Beginning balance, shares at Dec. 31, 2013		16,287,812
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	17,041	0	0	17,041	0	0
Other comprehensive income (loss), net of income tax benefit	3,054	0	0	0	3,054	0
Cash dividends declared ($0.60 per share)	(9,740)	0	0	(9,740)	0	0
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs	1,922	0	30	0	0	1,892
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs, shares		96,129
Exercise of stock options	184	0	11	0	0	173
Exercise of stock options, shares		9,500
Repurchase of cancelled restricted stock awards	0		735			(735)
Repurchase of cancelled restricted stock awards, shares		(43,452)
Stock-based compensation	792	0	792	0	0	0
Net tax deficiency on stock-based compensation	(2)	0	(2)	0	0	0
Purchases of treasury stock	(3,943)	0	0	0	0	(3,943)
Purchases of treasury stock, shares		(204,044)
Restricted stock awards granted	0		(1,349)			1,349
Restricted stock awards granted, shares		74,304
Ending balance at Sep. 30, 2014	$ 289,814	$ 91,332	$ 62,634	$ 179,903	$ (6,901)	$ (37,154)
Ending balance, shares at Sep. 30, 2014		16,220,249