Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319

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- Definition

Expiration date of each operating loss carryforward included in operating loss carryforward, in CCYY-MM-DD format.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
Income Taxes (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Earliest Tax Year [Member]
Operating Loss Carryforwards [Line Items]
Expiration date	Dec. 31, 2018
Latest Tax Year [Member]
Operating Loss Carryforwards [Line Items]
Expiration date	Dec. 31, 2037
Federal [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards		$ 373.3
Federal [Member] \| Unrestricted [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards		236.9
State [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards		236.3
State [Member] \| Unrestricted [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards		$ 236.3