Reconciliation of income taxes using federal statutory rate to effective income tax rate (Details)	4 Months Ended	8 Months Ended	12 Months Ended
Apr. 22, 2016	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2015
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			35.00%
Predecessor [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%			35.00%
Reconciliations of income taxes computed using the U.S. Federal statutory rate to the effective income tax rates
State tax provisions (benefits), net of federal benefits	0.90%			1.00%
Reorganization Adjustments	(1.80%)			0.00%
Expired operating loss carryovers	0.00%			0.00%
Change in enacted tax rates	0.00%			0.00%
Executive compensation limitation	0.00%			0.00%
Other, net	1.00%			(0.10%)
Valuation allowance adjustments	(35.10%)			(31.30%)
Effective rate	0.00%			4.60%
Successor [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		35.00%	35.00%
Reconciliations of income taxes computed using the U.S. Federal statutory rate to the effective income tax rates
State tax provisions (benefits), net of federal benefits		0.90%	1.60%
Reorganization Adjustments		0.00%	0.00%
Expired operating loss carryovers		(74.90%)	13.90%
Change in enacted tax rates		0.00%	55.60%
Executive compensation limitation		0.00%	0.60%
Other, net		0.20%	2.30%
Valuation allowance adjustments		38.90%	(111.80%)
Effective rate		0.00%	(2.80%)

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
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-Section S99
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-Subparagraph (SX 210.4-08.(h)(2))
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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Percentage of the difference, between reported income tax expense (benefit) and the expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations, that is attributable to tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority interest income (expense), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, change in enacted tax rate, prior year income taxes, change in deferred tax asset valuation allowance, and other adjustments.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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