STOCK-BASED COMPENSATION (Analysis of Stock Options Award Activity) (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($)
Shares
Outstanding at beginning of period (in shares) | shares	1,120,677
Granted (in shares) | shares	159,709
Exercised (in shares) | shares	(173,635)
Forfeited or expired (in shares) | shares	(5,700)
Outstanding at end of period (in shares) | shares	1,101,051	1,120,677
Exercisable at end of period (in shares) | shares	495,089
Weighted-Average Exercise Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 29.08
Granted (in dollars per share) | $ / shares	41.75
Exercised (in dollars per share) | $ / shares	27.52
Forfeited or expired (in dollars per share) | $ / shares	28.66
Outstanding at end of period (in dollars per share) | $ / shares	31.16	$ 29.08
Exercisable at end of period (in dollars per share) | $ / shares	$ 26.77
Outstanding at end of period, weighted-average remaining life (in years)	6 years 6 months 7 days
Exercisable at end of period, weighted-average remaining life (in years)	3 years 2 months 19 days
Outstanding at end of period, aggregate intrinsic value | $	$ 15,875
Exercisable at end of period, aggregate intrinsic value | $	9,311
Intrinsic value of options exercised | $	$ 3,159	$ 4,339	$ 1,546