Revenue Recognition (Adoption of ASC 606) - Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 82,715	$ 171,222
Products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	64,719	135,764
Services
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	17,996	35,458
Intercompany
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Intercompany | Products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Intercompany | Services
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Western Hemisphere | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	53,916	105,434
Western Hemisphere | Operating Segments | Products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	43,999	86,434
Western Hemisphere | Operating Segments | Services
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	9,917	19,000
Eastern Hemisphere | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	19,687	45,526
Eastern Hemisphere | Operating Segments | Products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	14,539	34,404
Eastern Hemisphere | Operating Segments | Services
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	5,148	11,122
Asia-Pacific | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	9,112	20,262
Asia-Pacific | Operating Segments | Products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	6,181	14,926
Asia-Pacific | Operating Segments | Services
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 2,931	$ 5,336