Commitments and Contingencies - Additional Information (Detail)		7 Months Ended	12 Months Ended
	Jun. 24, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) $ / bbl	Dec. 31, 2019 USD ($)
Commitments and Contingencies Additional Textual [Abstract]
Remaining environmental accrued liability recorded		$ 0	$ 0	$ 0
Obligatory monthly deposit into sinking fund account per barrel of oil | $ / bbl			0.25
Sinking fund account maximum value upon which obligation ceases			$ 4,300,000
Beta's decommissioning obligations, previously supported by surety bonds			71,300,000
Beta's decommissioning obligations, cash			90,200,000
Proceeds from Beta Decommissioning Trust account	$ 90,000,000.0
Beta's decommissioning obligations, full supported by surety bonds			161,300,000
Beta's decommissioning remaining obligations, cash			300,000
Rent expense			8,300,000	$ 7,500,000
Commitment fee/expense		$ 700,000	2,100,000
Commitment fee/expense			1,800,000
SPBPC Collateral Contractual pipeline and surface facilities abandonment [Member]
Commitments and Contingencies Additional Textual [Abstract]
Restricted Investment - decommissioning of offshore production facilities			$ 4,600,000