Revenue Recognition - Revenues From Contracts With Customers (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation Of Revenue [Line Items]
Revenues	$ 83,883	$ 93,808	$ 170,255	$ 177,718
Western Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	49,961	48,044	102,389	94,265
Asia Pacific | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	16,113	16,355	27,540	30,422
Eastern Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	17,809	29,409	40,326	53,031
Products
Disaggregation Of Revenue [Line Items]
Revenues	63,133	77,233	130,691	142,667
Products | Western Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	36,797	38,883	78,269	75,259
Products | Asia Pacific | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	12,120	13,810	20,027	24,250
Products | Eastern Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	14,216	24,540	32,395	43,158
Services
Disaggregation Of Revenue [Line Items]
Revenues	20,750	16,575	39,564	35,051
Services | Western Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	13,164	9,161	24,120	19,006
Services | Asia Pacific | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	3,993	2,545	7,513	6,172
Services | Eastern Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	$ 3,593	$ 4,869	$ 7,931	$ 9,873