Financial Instruments and Fair Value Disclosures - Assets Measured at Fair Value on Nonrecurring Basis (Detail) - USD ($) $ in Thousands	4 Months Ended	6 Months Ended	12 Months Ended
	Apr. 23, 2021	Jun. 30, 2020	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment of assets	$ 197,027	$ 774,028
Nonrecurring Fair Value Measurements [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment of assets	$ 197,027		$ 842,016
Impaired assets			1,000
Fair Value, Inputs, Level 3 | Nonrecurring Fair Value Measurements [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired assets			$ 1,000