Details of Selected Balance Sheet Accounts - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, plant, equipment and seismic rental equipment	$ 195,987	$ 210,553
Less accumulated depreciation	(143,834)	(143,065)
Property, plant, equipment and seismic rental equipment, net	52,153	67,488
Depreciation and amortization under capital leases	15,200	20,300	$ 24,600
Buildings
Property, Plant and Equipment [Line Items]
Property, plant, equipment and seismic rental equipment	15,822	17,424
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant, equipment and seismic rental equipment	145,654	157,618
Seismic rental equipment
Property, Plant and Equipment [Line Items]
Property, plant, equipment and seismic rental equipment	1,677	1,557
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant, equipment and seismic rental equipment	3,869	3,905
Other
Property, Plant and Equipment [Line Items]
Property, plant, equipment and seismic rental equipment	$ 28,965	$ 30,049