Supplemental Financial Statement Information - Other Non-operating Income (Expense) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Nonoperating Income (Expense) [Abstract]
Rent and royalty income	$ 3.5	$ 1.4	$ 2.0
Net gains on property and investments	0.5	1.0	0.0
Other	0.0	0.0	(0.4)
Other income, net	$ 4.0	$ 2.4	$ 1.6

Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2443-110228

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