Income Taxes--Narrative (Details) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
	Mar. 21, 2017	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Line Items]
U.S federal corporate income tax rate		35.00%		35.00%
Decrease in net deferred tax assets				$ 112,715
Decrease in effective tax rate				95.00%
Adjustment related to share-based compensation				$ 8,200
Discrete item associated with federal and state valuation allowance		$ 408,039		408,039
Valuation allowance, Deferred tax asset, Increase (Decrease)				$ 359,181
Purchase or sale of stock percentage				5.00%
Offering stock period				3 years
Possible ownership change, evaluation period				2 years
Cancellation of indebtedness income, realized	$ 0
Plan of Reorganization
Income Tax Disclosure [Line Items]
Senior Notes and associated accrued interest	1,267,410
General unsecured claims	$ 2,439
Minimum
Income Tax Disclosure [Line Items]
Changes in beneficial ownership percentage				50.00%
State and Local Jurisdiction
Income Tax Disclosure [Line Items]
Operating loss carryforwards		1,121,523		$ 1,121,523
Internal Revenue Service (IRS)
Income Tax Disclosure [Line Items]
Operating loss carryforwards		919,097		919,097
Operating loss carryforwards, not subject to expiration		$ 13,668		$ 13,668
Scenario Forecast
Income Tax Disclosure [Line Items]
U.S federal corporate income tax rate			21.00%
Percentage of limitations on deductibility of interest expense			30.00%
Percentage of limitation on net federal operating loss carryforwards			80.00%