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, 2011	$ 272,979	$ 91,332	$ 58,495	$ 157,566	$ (6,101)	$ (28,313)
Beginning balance, shares at Dec. 31, 2011		16,702,376
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	20,872	0	0	20,872	0	0
Other comprehensive loss, net of income tax benefit	(819)	0	0	0	(819)	0
Cash dividends declared ($0.80 per share)	(13,411)	0	0	(13,411)	0	0
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs	2,515	0	0	(70)	0	2,585
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs, shares		150,579
Exercise of stock options, shares	0
Repurchase of cancelled restricted stock awards	0	0	300	0	0	(300)
Repurchase of cancelled restricted stock awards, shares		(13,125)
Stock-based compensation	4,544	0	4,544	0	0	0
Net tax deficiency on stock-based compensation	(84)	0	(84)	0	0	0
Purchases of treasury stock	(2,319)	0	0	0	0	(2,319)
Purchases of treasury stock, shares		(140,755)
Restricted stock awards granted	0	0	(1,154)	(134)	0	1,288
Restricted stock awards granted, shares		71,157
Ending balance at Dec. 31, 2012	284,277	91,332	62,101	164,823	(6,920)	(27,059)
Ending balance, shares at Dec. 31, 2012		16,770,232
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	21,189	0	0	21,189	0	0
Other comprehensive loss, net of income tax benefit	(3,035)	0	0	0	(3,035)	0
Cash dividends declared ($0.80 per share)	(13,286)	0	0	(13,286)	0	0
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs	2,422	0	20	(32)	0	2,434
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs, shares		132,681
Exercise of stock options, shares	0
Repurchase of cancelled restricted stock awards	0	0	519	0	0	(519)
Repurchase of cancelled restricted stock awards, shares		(29,533)
Stock-based compensation	978	0	978	0	0	0
Net tax deficiency on stock-based compensation	(27)	0	(27)	0	0	0
Purchases of treasury stock	(12,012)	0	0	0	0	(12,012)
Purchases of treasury stock, shares		(655,609)
Restricted stock awards granted	0	0	(1,174)	(92)	0	1,266
Restricted stock awards granted, shares		70,041
Ending balance at Dec. 31, 2013	280,506	91,332	62,417	172,602	(9,955)	(35,890)
Ending balance, shares at Dec. 31, 2013		16,287,812
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	22,231	0	0	22,231	0	0
Other comprehensive loss, net of income tax benefit	(4,507)	0	0	0	(4,507)	0
Cash dividends declared ($0.80 per share)	(12,982)	0	0	(12,982)	0	0
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs	2,462	0	43	0	0	2,419
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs, shares		124,151
Exercise of stock options	310	0	(5)	0	0	315
Exercise of stock options, shares	17,334	17,334
Repurchase of cancelled restricted stock awards	0	0	735	0	0	(735)
Repurchase of cancelled restricted stock awards, shares		(43,452)
Stock-based compensation	1,141	0	1,141	0	0	0
Net tax deficiency on stock-based compensation	(2)	0	(2)	0	0	0
Purchases of treasury stock	(4,605)	0	0	0	0	(4,605)
Purchases of treasury stock, shares		(238,542)
Restricted stock awards granted	0	0	(1,349)	0	0	1,349
Restricted stock awards granted, shares		74,304
Ending balance at Dec. 31, 2014	$ 284,554	$ 91,332	$ 62,980	$ 181,851	$ (14,462)	$ (37,147)
Ending balance, shares at Dec. 31, 2014	16,221,607	16,221,607