Revenue Recognition (Revenue from Non-Monetary Exchanges) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Nonmonetary Transaction [Line Items]
Seismic data library additions			$ 3,115	$ 10,119
Revenue recognized			6,175	7,897
Specific Data Licenses or Selections of Data [Member]
Nonmonetary Transaction [Line Items]
Revenue recognized	1,849	2,481	2,882	5,514
Acquisition Contracts [Member]
Nonmonetary Transaction [Line Items]
Revenue recognized	1,645	931	3,273	2,314
Solutions [Member]
Nonmonetary Transaction [Line Items]
Revenue recognized	0	69	20	69
Seismic Data Library [Member]
Nonmonetary Transaction [Line Items]
Seismic data library additions	$ 726	$ 5,113	$ 3,115	$ 10,119