SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Restructuring Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring liability	$ 700		$ 700		$ 400
Restructuring charge	611	$ 140	611	$ 1,147
Payment for restructuring liability			300
Post-employment Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring liability	300		300		100
Restructuring charge	400		400
Payment for restructuring liability	100		200
Exit Liabilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring liability	400		400		$ 300
Restructuring charge	$ 200		200
Payment for restructuring liability			$ 100