Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=51824106&loc=d3e2420-110228

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

Name:	us-gaap_AssetImpairmentCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Seismic Data Library (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Seismic Data Library (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Oct. 01, 2015
Seismic Data Library
Straight-line amortization period			4 years
Internal data processing costs capitalized	$ 1,000	$ 900	$ 2,700	$ 2,800
Lowest amortization rate using the income forecast method			70.00%
Actual aggregate rate of amortization					70.00%
Asset impairment charges			$ 0	$ 0