Business Combinations - Business Combinations Purchase Price Allocation (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 05, 2018	Dec. 31, 2018	Dec. 31, 2017
Schedule of Assets and Liabilities Acquired in a Business Combination [Line Items]
Current Assets	$ 86,701
Property, plant, and equipment	$ 27,670
Weighted average useful life of property, plant and equipment acquired	6 years
Other long-term assets	$ 3,866
Identifiable intangible assets	226,700
Weighted average useful life, acquired intangible assets		8 years
Total identified intangible assets	241,100
Goodwill		$ 575,750	$ 59,675
Current liabilities	(99,406)
Customer contracts and relationships		(23,900)	$ 0
Long-term liabilities	(2,565)
SIlver Spring Networks, Inc. [Member]
Schedule of Assets and Liabilities Acquired in a Business Combination [Line Items]
Goodwill		$ 575,800
Total net assets acquired	809,216
Core Developed Technology [Member]
Schedule of Assets and Liabilities Acquired in a Business Combination [Line Items]
Identifiable intangible assets	81,900
Weighted average useful life, acquired intangible assets		5 years
Customer Contracts And Relationships [Member]
Schedule of Assets and Liabilities Acquired in a Business Combination [Line Items]
Identifiable intangible assets	134,000
Weighted average useful life, acquired intangible assets		10 years
Customer contracts and relationships	(23,900)
Weighted average useful life, acquired intangible liabilities		5 years
Trademarks and Trade Names [Member]
Schedule of Assets and Liabilities Acquired in a Business Combination [Line Items]
Identifiable intangible assets	10,800
Weighted average useful life, acquired intangible assets		3 years
In Process Research and Development [Member]
Schedule of Assets and Liabilities Acquired in a Business Combination [Line Items]
Identifiable intangible assets	$ 14,400