Summary of Significant Accounting Policies - Goodwill and Other Intangibles (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Goodwill and Other Intangibles
Goodwill impairment | $	$ 0	$ 0	$ 0
As Previously Reported
Goodwill and Other Intangibles
Number of reporting units | segment	2
Patents
Goodwill and Other Intangibles
Estimated useful lives of assets	20 years
Minimum | Proprietary Technology
Goodwill and Other Intangibles
Estimated useful lives of assets	3 years
Minimum | Customer Relationships
Goodwill and Other Intangibles
Estimated useful lives of assets	5 years
Maximum | Proprietary Technology
Goodwill and Other Intangibles
Estimated useful lives of assets	7 years
Maximum | Customer Relationships
Goodwill and Other Intangibles
Estimated useful lives of assets	12 years