Discontinued Operations - Assets and Liabilities of Discontinued Operations (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations
Current assets of discontinued operations	$ 0.0	$ 21.6
Non-current assets of discontinued operations	0.0	47.0
Current liabilities of discontinued operations	0.0	5.9
Non-current liabilities of discontinued operations	$ 0.0	0.2
Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations
Accounts receivable, net		11.0
Inventories, net		9.4
Prepaid expenses		0.3
Other current assets		0.9
Property, plant, and equipment, net		6.8
Goodwill		33.5
Identifiable intangible assets, net		6.7
Accounts payable		4.2
Customer advances and billings in excess of contract revenue		0.1
Accrued salaries, wages, and benefits		1.5
Current portion of warranty reserve		0.1
Other long-term liabilities		$ 0.2