STOCK PLANS (Summary of Stock Option Activity) (Details) - Stock options	12 Months Ended
	Dec. 31, 2017 $ / shares shares
Stock Options, Shares
Balance at beginning of year | shares	1,609,702
Options granted | shares	182,615
Options exercised | shares	(401,233)
Options canceled | shares	(28,636)
Balance at end of year | shares	1,362,448
Exercisable at end of year | shares	952,889
Stock Options, Weighted Average Exercise Price
Balance at beginning of year, weighted average exercise price (in dollars per share) | $ / shares	$ 51.32
Shares granted, weighted average exercise price (in dollars per share) | $ / shares	85.43
Shares exercised, weighted average exercise price (in dollars per share) | $ / shares	41.44
Shares canceled, weighted average exercise price (in dollars per share) | $ / shares	68.18
Balance at end of year, weighted average exercise price (in dollars per share) | $ / shares	58.45
Exercisable at end of year, weighted average exercise price (in dollars per share) | $ / shares	$ 52.57