Debt (Senior Notes) (Details) - USD ($) $ in Thousands		2 Months Ended	4 Months Ended	8 Months Ended	12 Months Ended
		Feb. 29, 2016	Dec. 31, 2016	Aug. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 02, 2016
Debt Instrument [Line Items]
Cash Payments For Interest On Debt			$ 7,500
Percentage of principal amount outstanding in exchange for common equity interest			100.00%
Principal amount outstanding			$ 668,000
Percentage of common equity interest			90.00%				90.00%
Predecessor
Debt Instrument [Line Items]
Cash Payments For Interest On Debt				$ 53,700	$ 98,500	$ 58,700
Gain on early extinguishment of debt	[1]			26,498
Amortization of financing costs				$ 900
7.75% Senior Notes | Predecessor
Debt Instrument [Line Items]
Repurchase of senior unsecured notes		$ 20,300
9.25% Senior Notes | Predecessor
Debt Instrument [Line Items]
Repurchase of senior unsecured notes		12,100
Senior Notes | Predecessor
Debt Instrument [Line Items]
Repurchase of senior unsecured notes face amount		5,500
Cash Payments For Interest On Debt		$ 600

[1] Gain (loss) on asset sales and disposal, reorganization items, net, gain on early extinguishment of debt, interest expense and income tax (expense) benefit have not been allocated to reportable segments as it would be impracticable to reasonably do so for the periods presented.