Income Taxes - Narrative (Details) $ in Millions	3 Months Ended	12 Months Ended
Dec. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Income Tax Disclosure [Abstract]
Doubling bonus depreciation for five years, percent	100.00%	100.00%
Tax Cuts and Jobs Act of 2017, income tax benefit	$ 4.4
Tax Cuts and Jobs Act of 2017, Change in tax rate, bonus depreciation	3.2
Executive compensation limitation	$ 1.0	$ 1.0
Minimum
Income Tax Contingency [Line Items]
Deduction to effective income tax rate, percent		3.00%
Maximum
Income Tax Contingency [Line Items]
Deduction to effective income tax rate, percent		4.00%

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 deductions. Including, but not limited to, extraterritorial income exclusion deduction, qualified production activity deduction, dividend deduction, deduction for dividend paid to employee stock ownership plan, Medicare prescription drug benefit subsidy deduction, and other deductions.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I)
-URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817

Reference 3: 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

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration