CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance (in shares) at Dec. 31, 2013		7,579,913
Beginning Balance at Dec. 31, 2013	$ 231,096	$ 47,783	$ 195,660	$ (12,347)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	18,482		18,482
Other comprehensive income, net of tax	2,896			2,896
Stock-based compensation expense	453	$ 453
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings and tax benefit (shares)		23,037
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings and tax benefit	157	$ 157
Common stock repurchased (in shares)		(181,355)
Common stock repurchased	(7,155)	$ (7,155)
Cash dividends declared ($0.81 and $0.90 per share)	(6,017)		(6,017)
Ending Balance (in shares) at Sep. 30, 2014		7,421,595
Ending Balance at Sep. 30, 2014	239,912	$ 41,238	208,125	(9,451)
Beginning Balance (in shares) at Dec. 31, 2014		7,426,222
Beginning Balance at Dec. 31, 2014	245,109	$ 41,555	211,979	(8,425)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	19,260		19,260
Other comprehensive income, net of tax	2,074			2,074
Stock-based compensation expense	542	$ 542
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings and tax benefit (shares)		27,823
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings and tax benefit	512	$ 512
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	(537)	$ (537)
Cash dividends declared ($0.81 and $0.90 per share)	(7,557)		(7,557)
Ending Balance (in shares) at Sep. 30, 2015		7,454,045
Ending Balance at Sep. 30, 2015	$ 259,403	$ 42,072	$ 223,682	$ (6,351)