Acquisitions - Hysitron (Details) - USD ($) $ in Millions	Jan. 23, 2017	Mar. 31, 2018	Dec. 31, 2017
Allocation of Consideration Transferred:
Goodwill		$ 171.1	$ 169.8
Hysitron, Incorporated
Acquisitions
Ownership percentage acquired	100.00%
Consideration Transferred:
Cash paid	$ 27.9
Cash acquired	(0.7)
Contingent consideration	1.6
Total consideration transferred	28.8
Allocation of Consideration Transferred:
Accounts receivable, net	3.0
Inventories	3.8
Other current assets	0.2
Property, plant and equipment	0.6
Goodwill	16.6
Deferred taxes, net	(4.1)
Capital lease	(0.2)
Liabilities assumed	(3.4)
Total consideration transferred	28.8
Maximum potential future payments related to the contingent consideration	10.0
Customer relationships | Hysitron, Incorporated
Allocation of Consideration Transferred:
Intangible assets	$ 5.8
Amortization period for intangible assets acquired	7 years
Existing technology | Hysitron, Incorporated
Allocation of Consideration Transferred:
Intangible assets	$ 4.7
Amortization period for intangible assets acquired	5 years
Trade names | Hysitron, Incorporated
Allocation of Consideration Transferred:
Intangible assets	$ 1.2
Amortization period for intangible assets acquired	7 years
Other | Hysitron, Incorporated
Allocation of Consideration Transferred:
Property, plant and equipment	$ 0.6
Amortization period for intangible assets acquired	7 years