FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Level 2
FAIR VALUE MEASUREMENTS
Long-term debt	$ 559,509	$ 819,099
Total	559,509	819,099
Level 3 | Recurring
FAIR VALUE MEASUREMENTS
Contingent consideration	9,700	10,400
Total	$ 9,700	$ 10,400