Derivative Financial Instruments and Hedging Activities - Schedule of Derivative Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
Derivative asset, current	$ 8,913	$ 75,304
Assets, Fair Value, Long-term	661	13,888
Derivative liability, current	47,005	222
Liability, Fair Value, Long-term	2,364	4,220
Derivative Financial Instruments – current
Derivative [Line Items]
Derivative asset, current	8,913	75,304
Derivative liability, current	47,005	222
Derivative Financial Instruments – current \| Natural gas price derivatives
Derivative [Line Items]
Derivative asset, current	8,913	75,123
Derivative liability, current	45,158	0
Derivative Financial Instruments – current \| Oil price derivatives
Derivative [Line Items]
Derivative asset, current	0	181
Derivative liability, current	831	222
Derivative Financial Instruments – long-term
Derivative [Line Items]
Liability, Fair Value, Long-term	2,364	4,220
Derivative Financial Instruments – long-term \| Natural gas price derivatives
Derivative [Line Items]
Assets, Fair Value, Long-term	661	13,888
Liability, Fair Value, Long-term	0	4,220
Derivative Financial Instruments – long-term \| Oil price derivatives
Derivative [Line Items]
Liability, Fair Value, Long-term	1,308	0
Derivative Financial Instruments – long-term \| Interest rate derivatives
Derivative [Line Items]
Derivative liability, current	1,016	0
Liability, Fair Value, Long-term	$ 1,056	$ 0

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

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