Discontinued Operations - Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets of discontinued operations	$ 8.2	$ 58.6
Non-current assets of discontinued operations	0.0	38.8
Current liabilities of discontinued operations	7.0	29.2
Non-current liabilities of discontinued operations	6.3	6.0
Herley | Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	0.0	(0.9)
Accounts receivable, net and unbilled receivables, net	7.9	56.0
Inventoried costs	0.0	1.5
Other current assets	0.3	2.0
Current assets of discontinued operations	8.2	58.6
Property, plant and equipment, net	0.0	3.0
Goodwill	0.0	35.6
Other assets	0.0	0.2
Non-current assets of discontinued operations	0.0	38.8
Accounts payable	0.3	14.2
Accrued expenses	1.1	4.7
Accrued compensation	0.0	4.6
Billings in excess of cost and earnings on uncompleted contracts	0.0	4.3
Other current liabilities	5.6	1.4
Current liabilities of discontinued operations	7.0	29.2
Non-current liabilities of discontinued operations	$ 6.3	$ 6.0