STOCK-BASED PLANS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Weighted Average Exercise Price
Stock based compensation expense	$ 2,722	$ 1,696
Stock Options
Stock Options
Share based compensation costs capitalized	$ 600	0
Stock options outstanding at the beginning of the period (in shares)	1,086,040
Granted (in shares)	128,500
Forfeited (in shares)	(6,500)
Stock options outstanding at the end of the period (in shares)	1,208,040
Weighted Average Exercise Price
Stock options outstanding at the beginning of the period (in dollars per share)	$ 77.11
Granted (in dollars per share)	108.40
Forfeited (in dollars per share)	106.77
Stock options outstanding at the end of the period (in dollars per share)	$ 80.28
Stock based compensation expense	$ 1,600	$ 700