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	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	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
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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	27,268	$ 0	0	27,268	0	0
Other comprehensive loss, net of income tax benefit	(2,246)	0	0	0	(2,246)	0
Cash dividends declared ($0.80 per share)	(15,673)	0	0	(15,673)	0	0
Stock issued under dividend reinvestment and employee stock purchase plans	2,434	$ 0	52	0	0	2,382
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs, shares		123,391
Stock Issued During Period, Value, Acquisitions	76,666	$ 18,939	57,727	0	0	0
Stock Issued During Period, Shares, Acquisitions		3,787,866
Exercise of stock options	461	$ 0	(54)	0	0	515
Exercise of stock options, shares		27,999
Repurchase of cancelled restricted stock awards	0	$ 0	318	0	0	(318)
Repurchase of cancelled restricted stock awards, shares		(19,934)
Stock-based compensation	1,421	$ 0	1,421	0	0	0
Net tax deficiency on stock-based compensation	31	0	31	0	0	0
Purchases of treasury stock	(13,342)	$ 0	0	0	0	(13,342)
Purchases of treasury stock, shares		(675,754)
Restricted stock awards granted	0	$ 0	(1,195)	0	0	1,195
Restricted stock awards granted, shares		65,755
Ending balance at Dec. 31, 2015	361,574	$ 110,271	121,280	193,446	(16,708)	(46,715)
Ending balance, shares at Dec. 31, 2015		19,530,930
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	19,505	$ 0	0	19,505	0	0
Other comprehensive loss, net of income tax benefit	(2,746)	0	0	0	(2,746)	0
Cash dividends declared ($0.80 per share)	(18,435)	0	0	(18,435)	0	0
Stock issued under dividend reinvestment and employee stock purchase plans	2,472	$ 0	59	0	0	2,413
Stock issued under dividend reinvestment and employee stock purchase plans and other employee benefit programs, shares		115,269
Stock Issued During Period, Value, Acquisitions	144,146	$ 34,288	109,858	0	0	0
Stock Issued During Period, Shares, Acquisitions		6,857,529
Exercise of stock options	$ 4,968	$ 0	59	0	0	4,909
Exercise of stock options, shares	261,534	261,050
Repurchase of cancelled restricted stock awards	$ 0	$ 0	418	0	0	(418)
Repurchase of cancelled restricted stock awards, shares		(23,409)
Stock-based compensation	2,084	$ 0	2,084	0	0	0
Purchases of treasury stock	(8,359)	$ 0	0	0	0	(8,359)
Purchases of treasury stock, shares		(328,271)
Restricted stock awards granted	0	$ 0	(3,264)	0	0	3,264
Restricted stock awards granted, shares		176,255
Ending balance at Dec. 31, 2016	$ 505,209	$ 144,559	$ 230,494	$ 194,516	$ (19,454)	$ (44,906)
Ending balance, shares at Dec. 31, 2016	26,589,353	26,589,353