Derivative Instruments (Summary of Cash Settlement on Commodity Derivatives and Presentation in Partnership's Condensed Consolidated Statements of Operations) (Details) - USD ($) $ in Thousands		4 Months Ended	8 Months Ended	12 Months Ended
		Dec. 31, 2016	Aug. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Portion of settlements attributable to subsequent mark to market gains (losses)	[1]	$ (1,825)
Total cash settlements on commodity derivative contracts	[1]	(1,825)
Gains (losses) recognized on cash settlement	[2]	(532)
Gains (losses) recognized on open derivative contracts	[2]	(43,360)
Gains (losses) on mark-to-market derivatives		$ (43,892)
Predecessor
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Portion of settlements associated with gains (losses) previously recognized within accumulated other comprehensive income, net of prior year offsets	[1],[3]		$ 10,758	$ 86,328
Portion of settlements attributable to subsequent mark to market gains (losses)	[1]		89,041	92,732
Total cash settlements on commodity derivative contracts	[1]		99,799	179,060
Gains (losses) recognized on cash settlement	[2]		(16,570)	40,480
Gains (losses) recognized on open derivative contracts	[2]		(7,346)	226,743
Gains (losses) on mark-to-market derivatives			$ (23,916)	$ 267,223	$ 2,819

[1] For the Predecessor period from January 1, 2016 through August 31, 2016, excludes the effects of the $235.3 million, net of $8.2 million in hedge monetization fees, paid directly to the First Lien Credit Facility lenders upon the sale of substantially all of our Predecessor’s commodity hedge positions on July 25, 2016 and July 26, 2016.

[2] Recognized in gain (loss) on mark-to-market derivatives.

[3] Recognized in gas and oil production revenue.