Revenue Recognition (Revenue from Non-Monetary Exchanges) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Nonmonetary Transaction [Line Items]
Seismic data library additions	$ 177	$ 2,716
Non-cash revenue	177	635
Specific Data Licenses or Selections of Data [Member]
Nonmonetary Transaction [Line Items]
Non-cash revenue	177	578
Acquisition Contracts [Member]
Nonmonetary Transaction [Line Items]
Non-cash revenue	0	57
Seismic Data Library [Member]
Nonmonetary Transaction [Line Items]
Seismic data library additions	$ 177	$ 2,716