Pension Plan and Employee Benefits, 401 (K) Plans (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Apr. 12, 2016	Sep. 30, 2016	Sep. 30, 2017
Defined Contribution Plan Disclosure [Line Items]
401(k) Plan expense	$ 1,386	$ 1,331
Other Subsidiaries [Member]
Defined Contribution Plan Disclosure [Line Items]
401(k) Plan expense	$ 234	$ 204
Successor
Defined Contribution Plan Disclosure [Line Items]
401(k) Plan expense				$ 2,440	$ 4,259
Successor | Other Subsidiaries [Member]
Defined Contribution Plan Disclosure [Line Items]
401(k) Plan expense				$ 378	$ 710
Predecessor
Defined Contribution Plan Disclosure [Line Items]
401(k) Plan expense			$ 1,593
Predecessor | Other Subsidiaries [Member]
Defined Contribution Plan Disclosure [Line Items]
401(k) Plan expense			$ 319