Business Combinations - Hudson Net Assets Acquired (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Sep. 20, 2017	Dec. 31, 2016
Net assets acquired:
Goodwill	$ 520.7	$ 459.7		$ 208.9
Hudson
Net assets acquired:
Goodwill	233.0	238.3
Identifiable intangible assets	211.0	211.0	$ 211.0
Accounts receivable	34.6	34.6
Property, plant and equipment	29.4	29.4
Inventories	26.5	26.5
Other current assets	8.1	8.1
Unbilled contract revenue	4.9	4.9
Other assets	2.7	2.9
Prepaid expenses	0.9	0.9
Deferred tax liabilities	(80.0)	(87.6)
Accounts payable	(21.2)	(21.2)
Customer advances and billings in excess of contract revenue	(17.4)	(17.4)
Accrued salaries, wages and benefits	(4.4)	(4.4)
Other current liabilities	(4.4)	(3.8)
Other long-term liabilities	(3.4)	(1.9)
Current portion of warranty reserve	(0.8)	(0.8)
Net assets acquired	419.5	$ 419.5
Adjustments
Goodwill	(5.3)
Other assets	(0.2)
Deferred tax liabilities	7.6
Other current liabilities	(0.6)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Other Long Term Liabilities	(1.5)
Net assets acquired	$ 0.0