COMMITMENTS AND CONTINGENCIES - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Outstanding letters of credit and surety bonds	$ 1,100,000		$ 1,100,000		$ 981,800
Aggregate purchase price	944,200		944,200		760,400
Legal accruals	21,000		21,000		23,500
Lease liabilities	81,642		81,642		$ 83,240
Operating lease expense	$ 4,200	$ 4,300	$ 12,200	$ 12,900