STOCK-BASED PLANS (Summary of Restricted Stock Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Weighted Average Grant Date Fair Value
Stock based compensation expense	$ 7,284	$ 8,200	$ 5,782
Restricted stock and stock option amortization	$ 7,284	$ 8,200	$ 5,782
Stock Options
Weighted Average Grant Date Fair Value
Weighted-average period for recognition of unamortized restricted stock expense	3 years 2 months 12 days
Restricted Stock
Restricted stock activity
Vesting period	5 years
Restricted stock outstanding at the beginning of the period (in shares)	172,690	122,334	57,933
Granted (in shares)	81,581	61,750	77,434
Vested (in shares)	(7,546)	(11,394)	(13,033)
Forfeited (in shares)	(4,169)
Restricted stock outstanding at the end of the period (in shares)	242,556	172,690	122,334
Weighted Average Grant Date Fair Value
Restricted stock outstanding at the beginning of the period (in dollars per share)	$ 92.02	$ 75.21	$ 65.72
Granted (in dollars per share)	121.81	126.38	79.77
Vested (in dollars per share)	147.56	97.72	60.15
Forfeited (in dollars per share)	101.33
Restricted stock outstanding at the end of the period (in dollars per share)	$ 100.15	$ 92.02	$ 75.21
Stock based compensation expense		$ 3,900	$ 2,200
Restricted stock and stock option amortization		$ 3,900	$ 2,200
Fair value of restricted stock vested	$ 1,100
Unamortized restricted stock expense	$ 14,300
Weighted-average period for recognition of unamortized restricted stock expense	3 years 2 months 23 days
Restricted Stock | General and Administrative Expense
Weighted Average Grant Date Fair Value
Stock based compensation expense	$ 4,700
Restricted stock and stock option amortization	$ 4,700