(Loss) Earnings Per Share - Reconciliations of Basic and Diluted Earnings (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	1 Months Ended		2 Months Ended	3 Months Ended	8 Months Ended		9 Months Ended
	Sep. 30, 2017		Aug. 31, 2017	Sep. 30, 2018	Aug. 31, 2017		Sep. 30, 2018
Numerator:
Net (loss) income	$ (821)	[1]		$ (6,655)			$ (20,309)
Denominator:
Weighted average common shares outstanding (in shares)	2,000			2,000			2,000
Effect of dilutive securities:
Outstanding common stock equivalents (in shares)	0			0			0
Denominator for diluted loss per common share (in shares)	2,000			2,000			2,000
Basic and diluted earnings (loss) per common share:
Basic (loss) earnings per common share	$ (0.41)			$ (3.33)			$ (10.15)
Diluted (loss) earnings per common share				(3.33)			(10.15)
Basic and diluted (loss) earnings per common share	$ (0.41)	[1]		$ (3.33)			$ (10.15)
Excluded outstanding share-based awards having an anti-dilutive effect (in shares)	1,734			1,803			1,803
Predecessor
Numerator:
Net (loss) income			$ 72,223		$ 36,190	[1]
Denominator:
Weighted average common shares outstanding (in shares)			31,790		32,174
Effect of dilutive securities:
Outstanding common stock equivalents (in shares)			0		0
Denominator for diluted loss per common share (in shares)			31,790		32,174
Basic and diluted earnings (loss) per common share:
Basic (loss) earnings per common share			$ 2.27		$ 1.12
Diluted (loss) earnings per common share			2.27		1.12
Basic and diluted (loss) earnings per common share			$ 2.27		$ 1.12	[1]
Excluded outstanding share-based awards having an anti-dilutive effect (in shares)			0		0

[1] * Adjusted due to the adoption of ASU No. 2017-07, "Compensation – Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost." See Note 3 - New Accounting Standards, for additional information.