Revenue Recognition - Contracts With Customers (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation Of Revenue [Line Items]
Revenues	$ 83,910
Intercompany
Disaggregation Of Revenue [Line Items]
Revenues	0
Western Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	46,221
Eastern Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	23,623
Asia Pacific | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	14,066
Products
Disaggregation Of Revenue [Line Items]
Revenues	65,434	$ 71,045
Products | Intercompany
Disaggregation Of Revenue [Line Items]
Revenues	0
Products | Western Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	36,376
Products | Eastern Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	18,618
Products | Asia Pacific | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	10,440
Services
Disaggregation Of Revenue [Line Items]
Revenues	18,476
Services | Intercompany
Disaggregation Of Revenue [Line Items]
Revenues	0
Services | Western Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	9,845
Services | Eastern Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	5,005
Services | Asia Pacific | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	$ 3,626