STOCK AWARD PLANS, Director Plan Stock Option Activity (Details) - Director Plan [Member]	3 Months Ended
	Mar. 31, 2018 $ / shares shares
Stock Award Plan Information [Abstract]
Shares available for future grants (in shares)	510,071
Stock Options [Member]
Stock Award Plan Information [Abstract]
Term of grant	10 years
Outstanding Non-Qualified or Nonincentive Stock Options [Roll Forward]
Outstanding at Period Start (in shares)	157,617
Exercised (in shares)	(12,000)
Outstanding at Period End (in shares)	145,617
Weighted Average Exercise Price [Abstract]
Outstanding at Period Start (in dollars per share) | $ / shares	$ 67.54
Exercised (in dollars per share) | $ / shares	55.49
Outstanding at Period End (in dollars per share) | $ / shares	$ 68.53
Restricted Stock [Member]
Stock Award Plan Information [Abstract]
Vesting period	6 months