REVENUES - Schedule of Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Contract Assets
Beginning balance, net of allowance	$ 1,195,145	$ 1,067,382
Additions, net of collections, and other	66,232	162,668
Bad debt, net of recoveries(1)	(24,598)	(34,905)	$ (20,300)
Ending balance, net of allowance	1,236,779	1,195,145	1,067,382
Accounts receivable from leases, net of allowance	338,391	313,225
Accounts receivable, net of allowance	1,575,170	1,508,370
Contract Liabilities
Beginning balance	184,000	193,913
Revenue recognized, included in beginning balance	(142,346)	(147,698)	(149,600)
Additions, net of revenue recognized during period, and other	146,950	137,785
Ending balance	188,604	184,000	$ 193,913
Deferred revenue from leases	49,703	38,027
Total deferred revenue	238,307	222,027
Less: Non-current portion, included in other long-term liabilities	30,112	40,476
Total deferred revenue, current portion	$ 208,195	$ 181,551