CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
CURRENT ASSETS
Cash and cash equivalents	$ 7,487	$ 9,772
Accounts receivable	72,255	68,181
Commodity derivative assets	13,329	0
Prepaid expenses and other current assets	1,765	1,036
TOTAL CURRENT ASSETS	94,836	78,989
PROPERTY AND EQUIPMENT
Oil and natural gas properties, at cost, using the successful efforts method of accounting, includes unproved properties of $730,435 and $605,736 at June 30, 2017 and December 31, 2016, respectively	2,850,183	2,697,073
Accumulated depreciation, depletion, amortization, and impairment	(1,707,534)	(1,652,930)
Oil and natural gas properties, net	1,142,649	1,044,143
Other property and equipment, net of accumulated depreciation of $14,341 and $14,327 at June 30, 2017 and December 31, 2016, respectively	542	528
NET PROPERTY AND EQUIPMENT	1,143,191	1,044,671
Deferred charges and other long-term assets	12,059	5,167
TOTAL ASSETS	1,250,086	1,128,827
CURRENT LIABILITIES
Accounts payable	3,533	4,142
Accrued liabilities	39,541	50,952
Commodity derivative liabilities	0	16,237
Other current liabilities	203	0
TOTAL CURRENT LIABILITIES	43,277	71,331
LONG-TERM LIABILITIES
Credit facility	393,000	316,000
Accrued incentive compensation	2,295	1,485
Commodity derivative liabilities	0	482
Deferred revenue	0	518
Asset retirement obligations	13,627	13,350
TOTAL LIABILITIES	452,199	403,166
COMMITMENTS AND CONTINGENCIES (Note 8)
MEZZANINE EQUITY
Partners' equity - convertible redeemable preferred units, 26 and 53 units outstanding at June 30, 2017 and December 31, 2016, respectively	27,085	54,015
EQUITY
Partners' equity - general partner interest	0	0
Noncontrolling interests	948	1,021
TOTAL EQUITY	770,802	671,646
TOTAL LIABILITIES, MEZZANINE EQUITY AND EQUITY	1,250,086	1,128,827
Common Units
EQUITY
Partners' equity - units	573,817	489,023
Subordinated Units
EQUITY
Partners' equity - units	$ 196,037	$ 181,602

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.