FAIR VALUE MEASUREMENTS - Fair Value of Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net liabilities	[1]	$ 1,127	$ 1,712
Net investment hedge
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net liabilities		(2,825)	(3,246)
Embedded derivative in convertible debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net liabilities		16,047	20,594
Quoted Prices in Active Markets for Identical Items (Level 1) | Contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net liabilities		0	0
Quoted Prices in Active Markets for Identical Items (Level 1) | Net investment hedge
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net liabilities		0	0
Quoted Prices in Active Markets for Identical Items (Level 1) | Embedded derivative in convertible debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net liabilities		0	0
Significant Other Observable Inputs (Level 2) | Contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net liabilities		0	0
Significant Other Observable Inputs (Level 2) | Net investment hedge
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net liabilities		(2,825)	(3,246)
Significant Other Observable Inputs (Level 2) | Embedded derivative in convertible debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net liabilities		16,047	20,594
Significant Unobservable Inputs (Level 3) | Contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net liabilities	[1]	1,127	1,712
Significant Unobservable Inputs (Level 3) | Net investment hedge
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net liabilities		0	0
Significant Unobservable Inputs (Level 3) | Embedded derivative in convertible debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net liabilities		$ 0	$ 0

[1] Inclusive of both current and noncurrent portions.