Revenue Recognition (Revenue from Non-Monetary Exchanges) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Nonmonetary Transaction
Seismic data library additions			$ 7,959	$ 177
Non-cash revenue			6,805	260
Specific Data Licenses or Selections of Data [Member]
Nonmonetary Transaction
Non-cash revenue	$ 913	$ 22	6,626	260
Acquisition Contracts [Member]
Nonmonetary Transaction
Non-cash revenue	2	0	166	0
Solutions [Member]
Nonmonetary Transaction
Non-cash revenue	13	0	13	0
Seismic Data Library [Member]
Nonmonetary Transaction
Seismic data library additions	$ 37	$ 0	$ 7,959	$ 177