STOCK AWARD PLANS, Employee Plan Outstanding and Exercisable Options (Details) - Employee Stock Award Plan [Member] - Stock Options [Member] $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) $ / shares shares
First Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	$ 51.23
Options Outstanding [Abstract]
Number Outstanding (in shares) | shares	126,140
Weighted Average Remaining Contractual Life	4 years 9 months 18 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 51.23
Options Exercisable [Abstract]
Number Exercisable (in shares) | shares	81,926
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 51.23
Second Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, lower limit (in dollars per share)	64.65
Range of Exercise Prices, upper limit (in dollars per share)	$ 75.50
Options Outstanding [Abstract]
Number Outstanding (in shares) | shares	487,672
Weighted Average Remaining Contractual Life	4 years 4 months 24 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 71.14
Options Exercisable [Abstract]
Number Exercisable (in shares) | shares	270,208
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 70.69
Third Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, lower limit (in dollars per share)	93.64
Range of Exercise Prices, upper limit (in dollars per share)	$ 96.85
Options Outstanding [Abstract]
Number Outstanding (in shares) | shares	33,987
Weighted Average Remaining Contractual Life	2 years 9 months 18 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 94.31
Options Exercisable [Abstract]
Number Exercisable (in shares) | shares	33,987
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 94.31
Fourth Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, lower limit (in dollars per share)	101.46
Range of Exercise Prices, upper limit (in dollars per share)	$ 104.37
Options Outstanding [Abstract]
Number Outstanding (in shares) | shares	28,188
Weighted Average Remaining Contractual Life	2 years 4 months 24 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 102.88
Options Exercisable [Abstract]
Number Exercisable (in shares) | shares	28,188
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 102.88
Full Exercise Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, lower limit (in dollars per share)	51.23
Range of Exercise Prices, upper limit (in dollars per share)	$ 104.37
Options Outstanding [Abstract]
Number Outstanding (in shares) | shares	675,987
Weighted Average Remaining Contractual Life	4 years 4 months 24 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 69.91
Aggregate Intrinsic Value, Options Outstanding | $	$ 6,080
Options Exercisable [Abstract]
Number Exercisable (in shares) | shares	414,309
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 69.15
Aggregate Intrinsic Value, Options Exercisable | $	$ 3,799