Employee Benefit Plans - Schedule of Net Benefit Costs (Details) - Pension and Other Postretirement Plans, Defined Benefit - USD ($) $ 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, 2016	Aug. 31, 2017	Sep. 30, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 38
Interest cost	397
Expected return on assets	(692)
Amortization of prior service cost	0
Amortization of actuarial loss	0
Net periodic pension and postretirement benefit (credit) cost	(257)
Contributions paid	$ 213
Predecessor
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost		$ 71	$ 112	$ 282	$ 336
Interest cost		806	1,312	3,227	3,936
Expected return on assets		(1,356)	(2,035)	(5,425)	(6,105)
Amortization of prior service cost		33	50	133	150
Amortization of actuarial loss		110	406	438	1,218
Net periodic pension and postretirement benefit (credit) cost		(336)	(155)	(1,345)	(465)
Contributions paid		$ 0	$ 0	$ 356	$ 0