Fair Value Measurements - Fair Value, Balance Sheet Grouping (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financial Assets
Commodity derivatives	$ 46,124	$ 108,455
Financial Liabilities
Commodity derivatives	0	0
Total
Financial Assets
Cash equivalents	0	12,188
Deferred compensation plan	1,778	1,392
Commodity derivatives	47,241	109,494
Financial Liabilities
Commodity derivatives	1,117	1,039
Level 1
Financial Assets
Cash equivalents	0	12,188
Deferred compensation plan	1,778	1,392
Commodity derivatives	0	0
Financial Liabilities
Commodity derivatives	0	0
Level 2
Financial Assets
Cash equivalents	0	0
Deferred compensation plan	0	0
Commodity derivatives	47,241	109,494
Financial Liabilities
Commodity derivatives	1,117	1,039
Level 3
Financial Assets
Cash equivalents	0	0
Deferred compensation plan	0	0
Commodity derivatives	0	0
Financial Liabilities
Commodity derivatives	$ 0	$ 0

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Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

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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. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or 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. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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