Acquisitions (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	6 Months Ended
	Jun. 04, 2014	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 03, 2014
Incentive Distribution Equity
Business Acquisition [Line Items]
Incentive Distribution Units issued in exchange for oil and natural gas properties			$ 30,800
WPX acquisition
Business Acquisition [Line Items]
Acquisition purchase price	$ 360,000
Equity interests issuable (in shares)	300,000
Schedule of allocation of the purchase price to the fair value of the acquired assets and liabilities assumed
Proved oil and natural gas properties including related equipment					$ 403,980
Future abandonment costs					(43,989)
Fair value of net assets acquired					$ 359,991
Pro Forma Operating Results
Revenues		$ 153,518		$ 301,270
Net loss attributable to unitholders		$ (21,722)		$ (16,091)
Loss per unit - basic and diluted (in dollars per share)		$ (0.38)		$ (0.28)
Basic and diluted (in shares)		57,372,000		57,341,000
WPX acquisition | Immediate vesting
Business Acquisition [Line Items]
Equity interests issuable (in shares)	100,000