FAIR VALUE MEASUREMENTS - Summary of Fair Value Level 3 Debt Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Term loan	$ 298,500	$ 291,000
Revolving credit facility	5,000	35,500
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Term loan	301,485	267,700
Revolving credit facility	$ 5,050	$ 32,600