Discontinued Operations - Loss, Assets and Liabilities of Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from discontinued operations, net of income taxes	$ (3.4)	$ (3.6)	$ (6.8)	$ (4.9)
Discontinued Operations, Held-for-sale or Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Other Assets, Current	0.3		0.3		$ 0.0
Disposal Group, Including Discontinued Operation, Assets	0.3		0.3		0.0
Liabilities:
Accounts payable and accrued expenses	54.2		54.2		54.0
Other noncurrent liabilities	126.5		126.5		141.1
Total liabilities classified as discontinued operations	$ 180.7		$ 180.7		$ 195.1