Summary of Significant Accounting Policies - Schedule of Derivative Contracts Volume and Prices (Detail)	Mar. 31, 2019 MMBTU bbl $ / bbl $ / MMBTU
Natural Gas Contracts, in MMBTU \| Swap Contracts for Q2,Q3 and Q4
Derivative [Line Items]
Volume \| MMBTU	16,200,000
Average price	3.00
Natural Gas Contracts, in MMBTU \| Swap Contracts for 2020
Derivative [Line Items]
Volume \| MMBTU	5,400,000
Average price	3.00
Natural Gas Contracts, in MMBTU \| Swap Contracts
Derivative [Line Items]
Volume \| MMBTU	21,600,000
Average price	3.00
Natural Gas Contracts, in MMBTU \| Collar Contracts for Q2,Q3 and Q4
Derivative [Line Items]
Volume \| MMBTU	32,754,500
Ceiling, Average price	3.46
Floor, Average price	2.43
Natural Gas Contracts, in MMBTU \| Collar Contracts for 2020
Derivative [Line Items]
Volume \| MMBTU	11,850,000
Ceiling, Average price	3.70
Floor, Average price	2.52
Natural Gas Contracts, in MMBTU \| Collar Contracts
Derivative [Line Items]
Volume \| MMBTU	44,604,500
Ceiling, Average price	3.52
Floor, Average price	2.46
Crude Oil Contracts, in Barrels \| Collar Contracts for Q2,Q3 and Q4
Derivative [Line Items]
Volume \| bbl	951,200
Ceiling, Average price \| $ / bbl	72.62
Floor, Average price \| $ / bbl	50.68
Crude Oil Contracts, in Barrels \| Collar Contracts for 2020
Derivative [Line Items]
Volume \| bbl	982,000
Ceiling, Average price \| $ / bbl	65.62
Floor, Average price \| $ / bbl	48.67
Crude Oil Contracts, in Barrels \| Collar Contracts
Derivative [Line Items]
Volume \| bbl	1,933,200
Ceiling, Average price \| $ / bbl	69.07
Floor, Average price \| $ / bbl	49.66

- Definition

Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

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- Definition

The average cap rate on a group of price risk derivatives such as caps or collars. A payment or receipt is triggered if the market rate exceeds the cap rate on the contract.

+ References

No definition available.

+ Details

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- Definition

The average floor rate on a group of price risk derivatives such as floors or collars. A payment or receipt is triggered if the market rate falls below the floor rate on the contract.

+ References

No definition available.

+ Details

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- Definition

The average forward price on the group of price risk forward or futures contracts, such as gas futures contracts.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Details

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