Stockholders' Equity - Reclassifications From Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period, net of tax	$ 0		$ 0
Predecessor
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period, net of tax		$ (214)		$ (428)
Prior service cost
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	0		0
Prior service cost | Predecessor
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax		(50)		(100)
Actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	0		0
Actuarial loss | Predecessor
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax		(164)		(328)
Defined Benefit Pension and Postretirement Items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	0		0
Tax effect	0		0
Total reclassifications for the period, net of tax	$ 0		$ 0
Defined Benefit Pension and Postretirement Items | Predecessor
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax		(214)		(428)
Tax effect		0		0
Total reclassifications for the period, net of tax		$ (214)		$ (428)