FAIR VALUE MEASUREMENTS - Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Contingent consideration
FAIR VALUE MEASUREMENTS
Asset (Liability)	$ (10,471)	$ (6,895)
Interest rate swaps
FAIR VALUE MEASUREMENTS
Asset (Liability)	(10,084)	(4,292)
Level 2 | Interest rate swaps
FAIR VALUE MEASUREMENTS
Asset (Liability)	(10,084)	(4,292)
Level 3 | Contingent consideration
FAIR VALUE MEASUREMENTS
Asset (Liability)	$ (10,471)	$ (6,895)