UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (65,215)	$ (293,586)
Adjustments to reconcile net loss to net cash provided by operating activities -
Depreciation, depletion and amortization	133,827	154,477
Impairment expense	0	277,495
Amortization and write-off of debt issuance costs, premium and discount	6,965	14,971
Amortization of non-cash costs on previously owned direct financing leases	0	(5,802)
Payments received under previously owned direct financing leases (Note 4)	35,000	10,334
Equity in earnings of investments in equity investees	(34,882)	(26,777)
Cash distributions of earnings of equity investees	34,325	25,923
Non-cash effect of long-term incentive compensation plans	2,884	(3,647)
Deferred and other tax liabilities	402	130
Unrealized losses (gains) on derivative transactions	32,377	(9,811)
Cancellation of debt income	0	(19,725)
Other, net	11,229	8,662
Net changes in components of operating assets and liabilities (Note 14)	31,272	19,518
Net cash provided by operating activities	188,184	152,162
CASH FLOWS FROM INVESTING ACTIVITIES:
Payments to acquire fixed and intangible assets	(111,412)	(69,438)
Cash distributions received from equity investees - return of investment	17,015	13,036
Proceeds from asset sales	32	304
Net cash used in investing activities	(94,365)	(56,098)
CASH FLOWS FROM FINANCING ACTIVITIES:
Borrowings on senior secured credit facility	366,600	684,500
Repayments on senior secured credit facility	(592,100)	(590,800)
Proceeds from issuance of senior unsecured notes (Note 9)	259,375	750,000
Net proceeds from issuance of preferred units (Note 10)	53,018	0
Repayment of senior unsecured notes (Note 9)	(80,859)	(820,713)
Debt issuance costs	(11,365)	(13,297)
Contributions from noncontrolling interests	385	1,844
Distributions to common unitholders	(36,774)	(85,805)
Distributions to preferred unitholders	(37,368)	(37,368)
Other, net	4,539	4,671
Net cash used in financing activities	(74,549)	(106,968)
Net increase (decrease) in cash, restricted cash, and cash equivalents	19,270	(10,904)
Cash, restricted cash and cash equivalents at beginning of period	27,018	56,405
Cash, restricted cash and cash equivalents at end of period	$ 46,288	$ 45,501