Employee Benefit Plans - Schedule of Net Benefit Costs (Details) - Pension and Other Postretirement Plans, Defined Benefit - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 117
Interest cost	1,225
Expected return on assets	(1,971)
Amortization of prior service cost	0
Amortization of actuarial loss	0
Net periodic pension and postretirement benefit gain	(629)
Contributions paid	$ 0
Predecessor
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost		$ 106
Interest cost		1,210
Expected return on assets		(2,034)
Amortization of prior service cost		50
Amortization of actuarial loss		164
Net periodic pension and postretirement benefit gain		(504)
Contributions paid		$ 356