Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	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, 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, net of income tax	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	$ 0	735	0	0	(735)
Repurchase of cancelled restricted stock awards, shares		(43,452)
Stock-based compensation	792	$ 0	792	0	0	0
Net tax benefit/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	$ 0	(1,349)	0	0	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
Beginning balance at Dec. 31, 2014	284,554	$ 91,332	62,980	181,851	(14,462)	(37,147)
Beginning balance, shares at Dec. 31, 2014		16,221,607
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	20,110	$ 0	0	20,110	0	0
Other comprehensive income, net of income tax	(517)	0	0	0	(517)	0
Cash dividends declared ($0.60 per share)	(11,801)	0	0	(11,801)	0	0
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs	1,836	$ 0	36	(1)	0	1,801
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs, shares		92,824
Issuance of common stock, acquisition	76,666	$ 18,939	57,727	0	0	0
Issuance of common stock, acquisition (shares)		3,787,866
Exercise of stock options	306	$ 0	(36)	0	0	342
Exercise of stock options, shares		18,666
Repurchase of cancelled restricted stock awards	0	$ 0	277	0	0	(277)
Repurchase of cancelled restricted stock awards, shares		(17,684)
Stock-based compensation	1,034	$ 0	1,034	0	0	0
Net tax benefit/deficiency on stock-based compensation	72	0	72	0	0	0
Purchases of treasury stock	(13,151)	$ 0	0	0	0	(13,151)
Purchases of treasury stock, shares		(666,421)
Restricted stock awards granted	0	$ 0	(1,195)	0	0	1,195
Restricted stock awards granted, shares		65,755
Ending balance at Sep. 30, 2015	$ 359,109	$ 110,271	$ 120,895	$ 190,159	$ (14,979)	$ (47,237)
Ending balance, shares at Sep. 30, 2015	19,502,613	19,502,613