EARNINGS PER SHARE (Computation of Basic and Diluted Earnings Per Share) (Details) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($) $ / shares shares	Sep. 30, 2016 USD ($) $ / shares shares	Sep. 30, 2017 USD ($) $ / shares shares	Sep. 30, 2016 USD ($) $ / shares shares
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income | $	$ 11,339	$ 10,903	$ 31,649	$ 29,165
Dividends and undistributed earnings allocated to participating securities | $	(46)	(54)	(134)	(134)
Net income available to common shareholders | $	$ 11,293	$ 10,849	$ 31,515	$ 29,031
Weighted-average common shares outstanding for basic EPS	15,515,189	15,425,452	15,505,698	15,410,310
Dilutive effect of stock-based awards (shares)	73,819	82,109	74,374	73,010
Weighted-average common and potential common shares for diluted EPS (shares)	15,589,008	15,507,561	15,580,072	15,483,320
Basic EPS (in dollars per share) | $ / shares	$ 0.72	$ 0.70	$ 2.03	$ 1.88
Diluted EPS (in dollars per share) | $ / shares	$ 0.72	$ 0.70	$ 2.02	$ 1.88
Stock split conversion ratio		1.5	1.5
Employee Stock Option
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Stock options (shares)	0	0	0	18,375