Statement Of Cash Flow Information (Restricted Cash and Non-Cash Additions) (Details)	6 Months Ended
	Jun. 30, 2012 USD ($)	Jun. 30, 2011 USD ($)	Jun. 30, 2012 Seismic Operations Bonds [Member] USD ($)	Dec. 31, 2011 Seismic Operations Bonds [Member] USD ($)	Dec. 31, 2011 Company Issued Credit Cards [Member] CAD
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and cash equivalents			$ 360,000	$ 122,000	125,000
Non-Cash Additions to Seismic Data Library:
Non-monetary exchanges related to resale licensing revenue	709,000	6,016,000
Non-monetary exchanges from underwriting of new data acquisition	1,680,000	1,139,000
Other non-monetary exchanges	0	86,000
Less: Non-monetary exchanges for data in progress	0	(2,235,000)
Total non-cash additions to seismic data library	$ 2,389,000	$ 5,006,000