COMMITMENTS AND CONTINGENCIES - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Outstanding letters of credit and surety bonds	$ 746,300	$ 623,300
Legal accruals	24,600	12,700
Lease liabilities	79,724	42,317
Operating lease expense	$ 3,800	$ 2,100