REVENUE - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Property Subject to or Available for Operating Lease [Line Items]
Operating leases	$ 6,981,951		$ 6,981,951		$ 6,914,796
Accumulated depreciation	1,487,408		1,487,408		$ 1,343,898
Assets Leased to Others | Tolling, Storage and Pipeline Transportation Services
Property Subject to or Available for Operating Lease [Line Items]
Operating leases	238,600		238,600
Accumulated depreciation	33,300		33,300
Depreciation expense	$ 1,000	$ 900	$ 2,800	$ 2,700