Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net income (loss)	$ (3,329)	$ 32,132
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Depreciation, depletion and amortization	17,813	11,341
Amortization of debt issuance costs	391	377
Revisions to asset retirement obligation included in DD&A		(862)
Asset impairments	4,688	1,309
Accretion expense	647	901
Distributions from equity investments	5,329	750
Equity earnings in affiliate	(4,397)	(1,135)
Bad debt expense		35
(Gain)/loss from disposition of property and equipment	(2,386)	210
Total mark-to-market on commodity derivative contracts	(7,584)	2,664
Cash settlements on commodity derivative contracts	5,093	17,361
Cash settlements on terminated commodity derivative contracts	3,602	3,197
Premiums paid on derivative contracts		(3,197)
Unit-based compensation expense	2,646	2,042
Gain on embedded derivative		(43,204)
Amortization of intangible assets	10,204	10,345
Costs for plug and abandon activities	(46)	(142)
Changes in Operating Assets and Liabilities:
Accounts receivable	159	872
Accounts receivable - related entities	(1,042)	(5,025)
Prepaid expenses	(348)	(1,505)
Other assets	124	682
Accounts payable and accrued liabilities	6,416	(962)
Accounts payable and accrued liabilities - related entities	(1,033)	2,760
Royalties payable	(301)	(112)
Net cash provided by operating activities	36,646	30,834
Cash flows from investing activities:
Development of oil and natural gas properties	(148)	(2,706)
Proceeds from sale of oil and natural gas properties	5,510	38
Final settlement of oil and natural gas properties acquisition	1,468
Development of gathering and transportation assets	(29,058)
Purchases of equity investments	(10,380)	(40,002)
Net cash used in investing activities	(32,608)	(42,670)
Cash flows from financing activities:
Payments for offering costs	(611)	(226)
Proceeds from issuance of debt	45,500	39,000
Repayment of borrowings	(9,500)
Proceeds from issuance of preferred units		(87)
Repurchase of common units under repurchase program		(2,948)
Units tendered by employees for tax withholdings		(140)
Distributions to common unitholders	(18,530)	(4,815)
Proceeds from issuance of common units	1,290
Class B preferred unit cash distributions	(22,750)	(24,918)
Debt issuance costs	(27)
Net cash provided by (used in) financing activities	(4,628)	5,866
Net increase (decrease) in cash and cash equivalents	(590)	(5,970)
Cash and cash equivalents, beginning of period	957	6,571
Cash and cash equivalents, end of period	367	601
Supplemental disclosures of cash flow information:
Change in accrued capital expenditures	2,414	1,562
Change in asset retirement obligations	198
Cash paid during the period for interest	5,494	$ 3,085
Earnout liability	$ 221