FAIR VALUE MEASUREMENTS - Acquisition Related Contingent Consideration (Details) - Recurring basis - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Business Combination, Acquisition Related Contingent Consideration [Roll Forward]
Balance, beginning	$ 11,637
Balance, ending	59,021	$ 11,637
Significant unobservable inputs (Level 3)
Business Combination, Acquisition Related Contingent Consideration [Roll Forward]
Balance, beginning	11,637	0
Present value of contingent consideration related to Chenodal/Manchester acquisition, upon acquisition	39,107	12,800
Increase from revaluation of contingent consideration	13,778
Decrease of contingent consideration, asset divestiture	(604)
Contractual Payments	(3,938)	(1,163)
Contractual Payments accrued at December 31, 2015	(959)
Balance, ending	$ 59,021	$ 11,637