UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
CURRENT ASSETS:
Cash and cash equivalents	$ 24,205	$ 21,282
Restricted cash	22,083	5,736
Accounts receivable - trade, net	433,310	392,465
Inventories	78,327	99,877
Other	61,796	60,809
Total current assets	619,721	580,169
FIXED ASSETS, at cost	5,312,157	5,173,475
Less: Accumulated depreciation	(1,437,510)	(1,322,141)
Net fixed assets	3,874,647	3,851,334
MINERAL LEASEHOLDS, net of accumulated depletion	550,959	552,575
EQUITY INVESTEES	302,940	319,068
INTANGIBLE ASSETS, net of amortization	127,947	128,742
GOODWILL	301,959	301,959
RIGHT OF USE ASSETS, net	144,013	153,925
OTHER ASSETS, net of amortization	41,301	45,847
TOTAL ASSETS	5,963,487	5,933,619
CURRENT LIABILITIES:
Accounts payable - trade	301,676	198,433
Accrued liabilities	218,327	184,978
Total current liabilities	520,003	383,411
SENIOR SECURED CREDIT FACILITY, net	415,653	643,700
SENIOR UNSECURED NOTES, net	2,927,489	2,750,016
DEFERRED TAX LIABILITIES	13,719	13,317
OTHER LONG-TERM LIABILITIES	422,299	393,018
Total liabilities	4,299,163	4,183,462
MEZZANINE CAPITAL:
Class A Convertible Preferred Units, 25,336,778 issued and outstanding at June 30, 2021 and December 31, 2020	790,115	790,115
Redeemable noncontrolling interests, 201,705 and 141,249 preferred units issued and outstanding at June 30, 2021 and December 31, 2020, respectively	204,647	141,194
PARTNERS’ CAPITAL:
Common unitholders, 122,579,218 units issued and outstanding at June 30, 2021 and December 31, 2020	679,278	829,326
Accumulated other comprehensive loss	(9,122)	(9,365)
Noncontrolling interests	(594)	(1,113)
Total partners' capital	669,562	818,848
TOTAL LIABILITIES, MEZZANINE CAPITAL AND PARTNERS’ CAPITAL	$ 5,963,487	$ 5,933,619