Amount of amortization expense attributable to debt issuance costs.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(8))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(8))
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Name:	us-gaap_AmortizationOfFinancingCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Debt (Narrative) (Details) - USD ($) $ in Millions	4 Months Ended	8 Months Ended	12 Months Ended
Debt (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Aug. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Cash Payments For Interest On Debt	$ 7.5
Non-revolving Credit Facility
Debt Instrument [Line Items]
Amortization expense of non-revolving credit facility	$ 0.2
Predecessor
Debt Instrument [Line Items]
Cash Payments For Interest On Debt		$ 53.7	$ 98.5	$ 58.7
Amortization expense of non-revolving credit facility		0.9
Predecessor \| Non-revolving Credit Facility
Debt Instrument [Line Items]
Amortization expense of non-revolving credit facility		$ 3.7	$ 4.4	$ 1.9