Industry Segments - Geographic information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended										12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013 Segment		Dec. 31, 2012		Dec. 31, 2011
Segment Reporting Information [Line Items]
Number of Operating Segments											1
Revenue	$ 59,569		$ 44,410	$ 47,544	$ 51,351	$ 70,327		$ 51,556	$ 46,028	$ 72,547	$ 202,874		$ 240,458		$ 218,008
Assets (1)	200,389	[1]				184,935	[1]				200,389	[1]	184,935	[1]	125,733	[1]
United States [Member]
Segment Reporting Information [Line Items]
Revenue											157,819		159,787		153,416
Assets (1)	123,555	[1]				105,486	[1]				123,555	[1]	105,486	[1]	66,168	[1]
Canada [Member]
Segment Reporting Information [Line Items]
Revenue											45,055		80,671		64,592
Assets (1)	$ 76,834	[1]				$ 79,449	[1]				$ 76,834	[1]	$ 79,449	[1]	$ 59,565	[1]

[1] Assets include net seismic data library and net property and equipment.