Proved developed and undeveloped reserve due to adjustments in drilling schedule.

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- Definition

Proved developed and undeveloped reserve previous estimate energy.

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No definition available.

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- Definition

Proved developed and undeveloped reserves revisions due to differential changes.

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No definition available.

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- Definition

Proved developed and undeveloped reserves revisions due to reductions downward in pricing and differentials.

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No definition available.

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- Definition

Proved developed and undeveloped reserves revisions due to (reductions) improvements in pricing.

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No definition available.

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- Definition

Proved developed and undeveloped reserves revisions offset due to change in five year development plan

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No definition available.

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- Definition

Proved developed and undeveloped reserves revisions offset due to change in well performance, capital allocation and lease operating expense.

+ References

No definition available.

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- Definition

Proved developed and undeveloped reserves revisions offset due to change in well spacing.

+ References

No definition available.

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- Definition

Proved developed and undeveloped reserves revisions offset due to non-development of reserves within five years.

+ References

No definition available.

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- Definition

Proved undeveloped reserve extension and discovery energy.

+ References

No definition available.

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- Definition

Number of development oil and gas wells incapable of producing either oil or gas in sufficient quantity to justify completion as oil or gas well.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1205
-Paragraph (a)
-Subparagraph (2)

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Number of development oil and gas wells capable of producing either oil or gas in sufficient quantity to justify completion as oil or gas well.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1205
-Paragraph (a)
-Subparagraph (2)

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- Definition

Energy measure of increase in quantity of proved reserve of oil and gas resulting from the extension of the proved acreage of previously discovered reservoir or discovery of new field with proved reserve or of new reservoir of proved reserve in old field, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher SEC
-Name Form 20-F
-Section Item 18
-Subsection Instruction 2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 5
-Subparagraph (d)
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- Definition

Energy measure of increase in quantity of proved reserve of oil and gas resulting from application of improved recovery techniques, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher SEC
-Name Form 20-F
-Section Item 18
-Subsection Instruction 2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447

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- Definition

Energy measure of increase in quantity of proved reserve of oil and gas resulting from purchase of mineral in place, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher SEC
-Name Form 20-F
-Section Item 18
-Subsection Instruction 2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 5
-Subparagraph (c)
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- Definition

Energy measure of increase (decrease) in quantity of proved reserve of oil and gas related to revision of a previous estimate resulting from new information, except for an increase in proved acreage, or change in economic factors, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher SEC
-Name Form 20-F
-Section Item 18
-Subsection Instruction 2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 5
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447

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- Definition

Energy measure of decrease in quantity of proved reserve of oil and gas resulting from sale of mineral in place, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher SEC
-Name Form 20-F
-Section Item 18
-Subsection Instruction 2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 5
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447

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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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Value of input used to measure alternative investment.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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Supplemental Oil and Natural Gas Information (unaudited) - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019 Bcfe	Dec. 31, 2018 Bcfe	Dec. 31, 2017 Bcfe Well
Reserve Quantities [Line Items]
Extensions	599.2	558.1	405.1
Developments	100.5	148.3
Revisions	(59.6)	(42.8)	695.6
Revisions due to (reductions) improvements in SEC pricing		15.0	607.2
Revisions due to changes in pricing differentials		6.8	61.4
Revision due to outperforming previous estimate		67.5	69.6
Revisions offset due to decision to not develop certain proved, undeveloped reserves within five years			42.6
Acquisition of proved developed, proved assets and proved undeveloped leasehold acreage	525.5	16.3	1.9
Divestiture of non-operated proved developed well		0.2
Revisions offset due to change in well spacing		(98.0)
Revisions offset due to change in five year development plan		(34.1)
Undeveloped extensions	498.7
Revisions due to downward in SEC pricing and differentials	(277.3)
Revision due to adjustments in drilling schedule	44.2
Revisions offset due to change in well performance, capital allocation and operating expense	261.9
Discount Rate [Member] \| Valuation Technique, Discounted Cash Flow [Member]
Reserve Quantities [Line Items]
Discount rate	10
Non-operated Well [Member]
Reserve Quantities [Line Items]
Developments	7.0
Utica [Member]
Reserve Quantities [Line Items]
Developments			361.0
Number of nonproductive development wells \| Well			1
Utica [Member] \| Non-operated Well [Member]
Reserve Quantities [Line Items]
Developments			0.3
Utica [Member] \| Operated Assets [Member]
Reserve Quantities [Line Items]
Developments	23.3	398.2
Undeveloped extensions	269.4
Ohio Marcellus [Member]
Reserve Quantities [Line Items]
Developments			43.8
Number of productive development wells \| Well			3
Marcellus Shale [Member] \| Operated Assets [Member]
Reserve Quantities [Line Items]
Developments	70.2	11.6
Undeveloped extensions	229.3