Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 17,135	$ 66,678
Adjustments to reconcile net income to net cash provided by operating activities -
Depreciation, depletion and amortization	244,811	176,453
Provision for leased items no longer in use	0	12,589
Gain on sale of assets	(3,363)	(26,684)
Amortization and write-off of debt issuance costs and discount	9,489	8,154
Amortization of unearned income and initial direct costs on direct financing leases	(9,847)	(10,374)
Payments received under direct financing leases	15,501	15,501
Equity in earnings of investments in equity investees	(28,388)	(34,805)
Cash distributions of earnings of equity investees	28,992	34,454
Non-cash effect of long-term incentive compensation plans	3,240	(5,524)
Deferred and other tax liabilities	380	508
Unrealized loss on derivative transactions	1,285	3,040
Other, net	999	(7,338)
Net changes in components of operating assets and liabilities (Note 14)	27,330	(26,262)
Net cash provided by operating activities	307,564	206,390
CASH FLOWS FROM INVESTING ACTIVITIES:
Payments to acquire fixed and intangible assets	(152,868)	(182,653)
Cash distributions received from equity investees - return of investment	26,042	25,917
Investments in equity investees	(2,960)	0
Acquisitions	0	(1,325,759)
Contributions in aid of construction costs	0	124
Proceeds from asset sales	36,859	39,204
Net cash used in investing activities	(92,927)	(1,443,167)
CASH FLOWS FROM FINANCING ACTIVITIES:
Borrowings on senior secured credit facility	759,800	1,247,700
Repayments on senior secured credit facility	(638,300)	(1,153,400)
Proceeds from issuance of senior unsecured notes	0	550,000
Proceeds from issuance of Class A convertible preferred units, net	0	729,958
Repayment of senior unsecured notes	(145,170)	0
Debt issuance costs	(242)	(17,808)
Issuance of common units for cash, net	0	140,513
Contributions from noncontrolling interest	1,980	1,850
Distributions to common unitholders	(191,224)	(260,586)
Other, net	1,356	1,215
Net cash provided by (used in) financing activities	(211,800)	1,239,442
Net increase in cash and cash equivalents	2,837	2,665
Cash and cash equivalents at beginning of period	9,041	7,029
Cash and cash equivalents at end of period	$ 11,878	$ 9,694