INCOME TAXES - Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Compensation	$ 52,538	$ 80,338
Receivables	8,819	13,471
Other	7,892	11,433
Deferred tax liabilities:
Intangible assets	(81,932)	(131,698)
Prepaid assets	(8,247)	(14,540)
Long-lived assets	(15,465)	(21,268)
Other	(2,090)	(608)
Net deferred tax liabilities	$ (38,485)	$ (62,872)