COMMITMENTS AND CONTINGENCIES - Cash Flows Related to Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Payments for operating lease liabilities	$ (18,250)	$ (9,570)
Cash flows from financing activities:
Principal payments on finance lease obligation	0	(1,054)
Supplemental Cash Flow Data:
Right-of-use assets obtained in exchange for operating lease obligations	$ 22,715	$ 255,553