REVENUE - Contract Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Change in Contract with Customer, Asset and Liability [Roll Forward]
Balance, beginning of the period	$ 39,223	$ 36,804
New deferred revenue	49,514	29,604
Reclassification to revenue during the year	(36,294)	(27,185)
Balance, end of the period	52,443	39,223
Less: long-term portion of deferred revenue	27,481	18,665
Current portion, end of the period	24,962	20,558
Revenue recognized	20,600	19,000
New deferred revenue during the year	15,700	$ 8,200
Performance obligation	41,700
Assets related to costs related to obtain contracts	11,300
Amortization of capitalized contract costs	7,500
Capitalized contract cost	$ 3,800