Summary of Significant Accounting Policies - Summary of Outstanding Commodity Derivatives (Detail) - Jun. 30, 2015 - Natural Gas Price Swap Agreements	$ / Mcf MMcf
Derivative [Line Items]
Commodity Derivatives Weighted Average Contract Price	3.20
Commodity Derivatives Volume | MMcf	3,600
Commodity Derivatives Beginning of Remaining Contract Period	Jul. 01, 2015
Commodity Derivatives End of Remaining Contract Period	Jun. 30, 2016