COMMITMENTS AND CONTINGENCIES - Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Leased Assets [Line Items]
Operating Leases, Rent Expense, Net	$ 40,100	$ 42,500	$ 45,400
Operating Leases, Income Statement, Sublease Revenue	6,500	$ 7,100	$ 2,700
Capital Leases, Future Minimum Payments Due	31,274
Corporate, Non-Segment [Member]
Operating Leased Assets [Line Items]
Capital Leases, Future Minimum Payments Due	$ 87,500