Segment and Geographical Area Information, Income Taxes Paid by Geographical Area (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information
Income Taxes Paid	$ 0.2	$ 0.2
Domestic
Segment Reporting Information
Income Taxes Paid	0.2	0.1
Foreign
Segment Reporting Information
Income Taxes Paid	$ 0.0	$ 0.1

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4297-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3536-108585

Name:	us-gaap_IncomeTaxesPaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration