Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income (loss)	$ (3,040)	$ 19,231
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Depreciation, depletion and amortization	21,262	21,901
Amortization of debt issuance costs	524	507
Revisions to asset retirement obligation included in DD&A		(1,858)
Asset impairments	4,688	7,646
Accretion of plugging and abandonment liability	773	1,127
Distributions (return on investment) from equity investments	8,720	2,950
Equity earnings in affiliate	(7,885)	(2,382)
Bad debt expense		35
(Gain) loss from disposition of property and equipment	(4,150)	210
Total mark-to-market on commodity derivative contracts	(3,947)	7,239
Cash settlements on commodity derivative contracts	5,487	18,780
Cash settlements on terminated commodity derivatives	3,602
Unit-based compensation	3,373	2,044
Loss on earnout derivative	2,353
Gain on embedded derivative		(47,794)
Amortization of intangible assets	13,568	13,756
Costs for plug and abandon activities	(60)	(183)
Changes in Operating Assets and Liabilities:
Accounts receivable	644	(159)
Accounts receivable - related entities	(6,590)	(4,472)
Prepaid expenses	(629)	(1,297)
Other assets	144	730
Accounts payable and accrued liabilities	9,997	(3,876)
Accounts payable and accrued liabilities- related entities	3,566	6,011
Royalties payable	(300)	17
Net cash provided by operating activities	52,100	40,163
Cash flows from investing activities:
Cash paid for acquisitions	1,468	(25,622)
Development of oil and natural gas properties	(441)	(939)
Proceeds from sale of assets	11,665	38
Construction of gathering and transportation assets	(31,693)	(4,730)
Purchases of and contributions to equity affiliates	(13,684)	(107,271)
Net cash used in investing activities	(32,685)	(138,524)
Cash flows from financing activities:
Payments for offering costs	(611)	(5,403)
Proceeds from issuance of debt	48,000	72,000
Repayment of debt	(12,000)	(26,000)
Issuance of common units	1,290	99,196
Repurchase of common units under repurchase program		(2,948)
Units tendered by employees for tax withholdings		(140)
Distributions to common unitholders	(25,192)	(6,696)
Class B preferred unit cash distributions	(31,500)	(37,168)
Debt issuance costs	(38)	(94)
Net cash provided by (used in) financing activities	(20,051)	92,747
Net decrease in cash and cash equivalents	(636)	(5,614)
Cash and cash equivalents, beginning of period	957	6,571
Cash and cash equivalents, end of period	321	957
Supplemental disclosures of cash flow information:
Change in accrued capital expenditures	1,064	1,119
Cash paid during the period for interest	$ 7,643	4,449
Transfer of embedded derivative to Class B preferred units		$ 145,283