Reportable Segments Segments Text Disclosure (Details) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2018 USD ($)	Jun. 30, 2018 USD ($) segments
Segment Reporting Information [Line Items]
Number of Reportable Segments \| segments		4
Income tax expense/ (benefit) related to sale of affiliate \| $	$ 12.7	$ 12.7

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

No definition available.

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration