Summary of Significant Accounting Policies - Multi-client Data Library Costs and Accumulated Amortization (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Multi-client data library capitalized income	$ 12,700	$ 6,600	$ 6,100
Multi Client Data Creation Cost [Abstract]
Gross costs of multi-client data creation	939,077	906,306
Less accumulated amortization	(727,872)	(680,770)
Less impairments to multi-client data library	(121,905)	(119,601)
Total	$ 89,300	$ 105,935