Acquisitions - 2015 (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2015	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2014
Allocation of Consideration Transferred:
Goodwill		$ 130.6	$ 169.8	$ 130.6	$ 127.8
Jordan Valley Semiconductors, LTD
Consideration Transferred:
Cash paid	$ 35.4
Cash acquired	(6.8)
Contingent consideration	4.1
Total consideration transferred	32.7
Allocation of Consideration Transferred:
Accounts receivable	3.8
Inventories	10.5
Other current assets	2.2
Property, plant and equipment	1.6
Goodwill	6.3
Liabilities assumed	(6.0)
Total consideration transferred	32.7
Additional consideration based on revenue and gross margin achievements		7.7
Maximum potential future payments related to the contingent consideration		$ 4.1
Jordan Valley Semiconductors, LTD | Customer relationships
Allocation of Consideration Transferred:
Intangible assets	$ 6.8
Amortization period for intangible assets acquired	7 years
Jordan Valley Semiconductors, LTD | Existing technology
Allocation of Consideration Transferred:
Intangible assets	$ 6.0
Amortization period for intangible assets acquired	7 years
Jordan Valley Semiconductors, LTD | Trade names
Allocation of Consideration Transferred:
Intangible assets	$ 1.5
Amortization period for intangible assets acquired	7 years