Summary of Significant Accounting Policies - Additional Information 4 (Detail) - USD ($) $ in Thousands	7 Months Ended	9 Months Ended
	Aug. 13, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Operations And Summary Of Significant Accounting Policies [Line Items]
Performance multiplier, minimum		0.00%
Performance multiplier, maximum		200.00%
Participating securities that share in losses		0
Convertible Notes
Operations And Summary Of Significant Accounting Policies [Line Items]
Interest paid in-kind	$ 25,000
Restricted Stock
Operations And Summary Of Significant Accounting Policies [Line Items]
Shares of unvested restricted stock outstanding		422,545
Predecessor
Operations And Summary Of Significant Accounting Policies [Line Items]
Participating securities that share in losses			0
Interest paid in-kind	$ 25,004		$ 28,194
Predecessor | Convertible Notes
Operations And Summary Of Significant Accounting Policies [Line Items]
Interest paid in-kind			$ 28,200
Predecessor | Restricted Stock
Operations And Summary Of Significant Accounting Policies [Line Items]
Shares of unvested restricted stock outstanding	904,181			619,867