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Derivative Activities - Derivative Volumes Hedged and Average Hedge Prices (Parenthetical) (Detail) - Call Swaptions - Natural Gas
Sep. 30, 2020
MMBTU / d
bbl / d
$ / MMBTU
$ / bbl
2021 Commodity Contract  
Derivative [Line Items]  
Volume Hedged | MMBTU / d 140,000
Weighted average price of hedge | $ / MMBTU 2.88
2022 Commodity Contract  
Derivative [Line Items]  
Volume Hedged | bbl / d 280,000
Weighted average price of hedge | $ / bbl 2.81