Fresh Start Accounting - Schedule of Settlement of Liabilities Subject to Compromise and Resulting Net Gain (Detail) - USD ($) $ in Thousands		4 Months Ended	8 Months Ended	12 Months Ended
	May 04, 2017	May 04, 2017	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Fresh Start Adjustment [Line Items]
Total liabilities subject to compromise of Predecessor	$ 0	$ 0
Gain on settlement of liabilities subject to compromise			$ 0	$ 0	$ 0
Predecessor [Member]
Fresh Start Adjustment [Line Items]
Gain on settlement of liabilities subject to compromise		758,764
Reorganization Adjustments [Member]
Fresh Start Adjustment [Line Items]
Total liabilities subject to compromise of Predecessor	1,162,437	1,162,437
Recognition of payables for general unsecured claims	(1,389)
Payment to holders of the Notes	(24,639)
Issuance of common stock to holders of the Notes	(377,645)
Gain on settlement of liabilities subject to compromise	758,764
Reorganization Adjustments [Member] | Predecessor [Member]
Fresh Start Adjustment [Line Items]
Accounts payable	1,389	1,389
Accrued interest payable	49,796	49,796
Debt	1,111,252	1,111,252
Total liabilities subject to compromise of Predecessor	$ 1,162,437	$ 1,162,437