COMMITMENTS AND CONTINGENCIES - Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Leases
Rent expense from continuing operations under leases	$ 28,700	$ 26,000	$ 21,700
Future minimum payments under the leases
2018	25,115
2019	24,015
2020	21,209
2021	19,101
2022	17,856
2023 and thereafter	90,832
Total	$ 198,128
Minimum
Operating Leases
Operating leases term	1 year
Maximum
Operating Leases
Operating leases term	40 years