Statement of Cash Flow Information (Non-Cash Additions and Non-Cash Revenue) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Non-monetary Transaction
Non-monetary exchanges related to resale licensing	$ 1,840	$ 9,300	$ 741
Non-monetary exchanges from underwriting of new data acquisition	408	0	209
Adjustment to prior year non-monetary exchange from underwriting of new data acquisition	0	(2)	0
Non-monetary exchanges related to data processing and reproduction services	392	13	0
Total non-cash additions to seismic data library	2,640	9,311	950
Non-cash revenue	3,308	6,928	1,071
Acquisition revenue on underwriting [Member]
Non-monetary Transaction
Non-cash revenue	129	168	38
Licensing revenue from specific data licenses and selections [Member]
Non-monetary Transaction
Non-cash revenue	3,179	6,747	1,033
Solutions revenue [Member]
Non-monetary Transaction
Non-cash revenue	$ 0	$ 13	$ 0