REVENUES - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Liabilities:
Contract liabilities, net (current)	$ 206,299	$ 193,405
Contract liabilities, net (noncurrent)	43,714	35,272
Obtain Contract
Assets:
Capitalized costs, net	243,489	226,945
Fulfill Contract
Assets:
Capitalized costs, net	$ 72,114	$ 38,150