Variable Interest Entities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	$ 163.5	$ 42.4
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	111.0
Liabilities	$ 8.8

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.

No definition available.

+ Details

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- Definition

Carrying amount of the assets in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph a
-URI http://asc.fasb.org/extlink&oid=77990344&loc=d3e5728-111685

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount of the liabilities in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

+ Details

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Period Type:	instant

- Details

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- Details

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