Revenue Recognition - Revenues From Contracts With Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Revenues	$ 84,229	$ 99,735	$ 254,484	$ 277,454
Western Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	47,069	53,618	149,458	147,883
Eastern Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	17,066	28,310	57,392	81,343
Asia Pacific | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	20,094	17,807	47,634	48,228
Products
Disaggregation Of Revenue [Line Items]
Revenues	66,451	81,851	197,142	224,518
Products | Western Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	36,095	42,561	114,364	117,820
Products | Eastern Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	13,377	23,656	45,772	66,815
Products | Asia Pacific | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	16,979	15,634	37,006	39,883
Services
Disaggregation Of Revenue [Line Items]
Revenues	17,778	17,884	57,342	52,936
Services | Western Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	10,974	11,057	35,094	30,063
Services | Eastern Hemisphere | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	3,689	4,654	11,620	14,528
Services | Asia Pacific | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	$ 3,115	$ 2,173	$ 10,628	$ 8,345