STOCK AWARD PLANS, Director Plan Stock Option Activity (Details) - Director Plan [Member]	9 Months Ended
	Sep. 30, 2018 $ / shares shares
Stock Award Plan Information [Abstract]
Shares available for future grants (in shares)	486,058
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
Granted (in shares)	2,640
Exercised (in shares)	(29,153)
Outstanding at Period End (in shares)	131,104
Weighted Average Exercise Price [Abstract]
Outstanding at Period Start (in dollars per share) | $ / shares	$ 67.54
Granted (in dollars per share) | $ / shares	85.30
Exercised (in dollars per share) | $ / shares	57.47
Outstanding at Period End (in dollars per share) | $ / shares	$ 70.14
Restricted Stock [Member]
Stock Award Plan Information [Abstract]
Vesting period	6 months