UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
CURRENT ASSETS:
Cash and cash equivalents	$ 10,407	$ 21,282
Restricted cash	5,089	5,736
Accounts receivable - trade, net	321,637	392,465
Inventories	87,220	99,877
Other	57,330	60,809
Total current assets	481,683	580,169
FIXED ASSETS, at cost	5,385,516	5,173,475
Less: Accumulated depreciation	(1,494,832)	(1,322,141)
Net fixed assets	3,890,684	3,851,334
MINERAL LEASEHOLDS, net of accumulated depletion	550,000	552,575
EQUITY INVESTEES	296,202	319,068
INTANGIBLE ASSETS, net of amortization	127,148	128,742
GOODWILL	301,959	301,959
RIGHT OF USE ASSETS, net	140,027	153,925
OTHER ASSETS, net of amortization	38,623	45,847
TOTAL ASSETS	5,826,326	5,933,619
CURRENT LIABILITIES:
Accounts payable - trade	176,091	198,433
Accrued liabilities	202,028	184,978
Total current liabilities	378,119	383,411
SENIOR SECURED CREDIT FACILITY, net	430,577	643,700
SENIOR UNSECURED NOTES, net	2,929,000	2,750,016
DEFERRED TAX LIABILITIES	13,947	13,317
OTHER LONG-TERM LIABILITIES	420,881	393,018
Total liabilities	4,172,524	4,183,462
MEZZANINE CAPITAL:
Class A Convertible Preferred Units, 25,336,778 issued and outstanding at September 30, 2021 and December 31, 2020	790,115	790,115
Redeemable noncontrolling interests, 246,394 and 141,249 preferred units issued and outstanding at September 30, 2021 and December 31, 2020, respectively	251,811	141,194
PARTNERS’ CAPITAL:
Common unitholders, 122,579,218 units issued and outstanding at September 30, 2021 and December 31, 2020	621,308	829,326
Accumulated other comprehensive loss	(9,000)	(9,365)
Noncontrolling interests	(432)	(1,113)
Total partners' capital	611,876	818,848
TOTAL LIABILITIES, MEZZANINE CAPITAL AND PARTNERS’ CAPITAL	$ 5,826,326	$ 5,933,619