Employee Benefit Plans - Schedule of Assumptions Used (Details) - Pension Plans, Defined Benefit	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2017	Aug. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Expected long-term rate of return on plan assets (as a percent)	5.00%
Minimum
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate (as a percent)	3.51%
Projected annual salary increases (as a percent)	0.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate (as a percent)	3.52%
Projected annual salary increases (as a percent)	0.00%
Maximum
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate (as a percent)	3.58%
Projected annual salary increases (as a percent)	3.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate (as a percent)	3.62%
Projected annual salary increases (as a percent)	3.00%
Predecessor
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate (as a percent)			4.00%
Expected long-term rate of return on plan assets (as a percent)		5.25%	5.25%
Predecessor | Minimum
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate (as a percent)		3.52%	3.70%
Projected annual salary increases (as a percent)		0.00%	0.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate (as a percent)		3.70%
Projected annual salary increases (as a percent)		0.00%	0.00%
Predecessor | Maximum
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate (as a percent)		3.62%	3.83%
Projected annual salary increases (as a percent)		3.00%	3.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate (as a percent)		3.83%
Projected annual salary increases (as a percent)		3.00%	3.00%