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Derivative Activities - Additional Information (Detail)
Mar. 31, 2017
USD ($)
MMBTU / d
t_per_M
MMBTU
bbl
Derivatives Excluding Basis Swaps and Freight Swaps  
Derivative [Line Items]  
Derivative assets liabilities at fair value net $ 8,800,000
Natural Gas | Basis Swaps  
Derivative [Line Items]  
Derivative assets liabilities at fair value net $ (20,400,000)
Volume Hedged | MMBTU 68,830,000
Natural Gas | Swaps | 2017  
Derivative [Line Items]  
Volume Hedged | MMBTU / d 844,245 [1]
Natural Gas | Swaps | 2018  
Derivative [Line Items]  
Volume Hedged | MMBTU / d 417,260
Propane | Spread Swaps  
Derivative [Line Items]  
Derivative assets liabilities at fair value net $ 491,000
Propane | Spread Swaps | 2017  
Derivative [Line Items]  
Volume Hedged | bbl 1,641,000
Propane | Spread Swaps | 2018  
Derivative [Line Items]  
Volume Hedged | bbl 750,000
Freight | Swaps  
Derivative [Line Items]  
Derivative assets liabilities at fair value net $ 116,000
Volume Hedged | t_per_M 5,000
[1] Includes derivative instruments assumed in connection with the MRD Merger.