Acquisitions - Assets Acquired (Details) - USD ($) $ in Millions	Oct. 30, 2018	Mar. 15, 2018
RPC Photonics, Inc.
Business Acquisition [Line Items]
Cash	$ 1.8
Other current assets	1.8
Property and equipment	2.6
Total liabilities	(0.5)
Net tangible assets acquired	$ 5.7
AW business
Business Acquisition [Line Items]
Cash		$ 16.1
Accounts receivable		43.0
Inventory		33.5
Property and equipment		33.5
Other assets		6.1
Accounts payable		(10.9)
Other liabilities		(28.4)
Deferred revenue		(10.2)
Deferred tax liabilities		(23.7)
Net tangible assets acquired		$ 59.0