Chapter 11 Proceedings - Schedule of Reorganization Items Incurred (Detail) - USD ($) $ in Thousands	3 Months Ended		4 Months Ended	5 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Apr. 23, 2021	Sep. 30, 2021	Sep. 30, 2020
Reorganizations [Abstract]
Professional fees	$ 1,916	$ 18,634	$ 51,084	$ 7,454	$ 39,293
Fresh start valuation adjustments			2,699,422
Net gain on settlement with certain unsecured vendors and liabilities subject to compromise		(9,971)	(1,129,892)
Accrued backstop commitment premium			10,424
Write-off of predecessor directors and officers tail insurance policy			6,932
Other			1,793		(4,205)
Write-off of debt issuance costs					27,552
Total reorganization items, net	$ 1,916	$ 8,663	$ 1,639,763	$ 7,454	$ 62,640