Revenue Recognition - Revenues From Contracts With Customers (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation Of Revenue [Line Items]
Revenues	$ 334,411	$ 375,297
Western Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	196,887	204,761
Eastern Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	70,370	104,566
Asia Pacific | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	67,154	65,970
Products
Disaggregation Of Revenue [Line Items]
Revenues	258,834	303,279	$ 265,052
Products | Western Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	151,351	162,067
Products | Eastern Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	56,038	86,057
Products | Asia Pacific | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	51,445	55,155
Services
Disaggregation Of Revenue [Line Items]
Revenues	75,577	72,018
Services | Western Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	45,536	42,694
Services | Eastern Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	14,332	18,509
Services | Asia Pacific | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	$ 15,709	$ 10,815