Statement of Cash Flow Information (Details)	12 Months Ended
Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Mar. 31, 2013 Seismic Operations Bonds [Member] USD ($)	Dec. 31, 2012 Seismic Operations Bonds [Member] USD ($)	Dec. 31, 2011 Seismic Operations Bonds [Member] USD ($)	Mar. 31, 2013 Cash Posted As Security Against Company Issued Credit Cards for Olympic [Member] CAD	Dec. 31, 2012 Cash Posted As Security Against Company Issued Credit Cards for Olympic [Member] CAD	Dec. 31, 2011 Cash Posted As Security Against Company Issued Credit Cards for Olympic [Member] CAD
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and cash equivalents				$ 651,000	$ 651,000	$ 122,000	125,000	125,000	125,000
Income taxes paid	3,200,000	8,100,000	15,000
Income tax refunds	$ 1,000,000	$ 100,000	$ 68,000

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

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The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

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