RECEIVABLES, CONTRACT ASSETS, AND DEFERRED REVENUE RECEIVABLES, CONTRACT ASSETS, AND DEFERRED REVENUE - Summary of Contract Assets and Deferred Revenue (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Receivables [Abstract]
Contract assets		$ 3,711	$ 914
Long-term contract assets		2,543	0
Total contract assets		6,254	914
Deferred revenue	[1]	185,145	165,850
Long-term deferred revenue		5,344	3,706
Total deferred revenue		$ 190,489	$ 169,556

[1] On January 1, 2018, the Company adopted the ASC 606 revenue recognition standard and adjusted prior periods to conform. See "Note 2. Significant Accounting Policies" for additional information.