Acquisition - Additional Information (Detail) (USD $)	6 Months Ended	0 Months Ended
	Jul. 31, 2014	May 31, 2014 Seamap Pte Ltd [Member] Ion Geophysical Corporation [Member] Product_Lines	May 31, 2014 Seamap Pte Ltd [Member] Ion Geophysical Corporation [Member] Furniture and Fixtures [Member]	May 31, 2014 Seamap Pte Ltd [Member] Ion Geophysical Corporation [Member] Intangible assets [Member]	May 31, 2014 Seamap Pte Ltd [Member] Ion Geophysical Corporation [Member] Inventory [Member]	May 31, 2014 Seamap Pte Ltd [Member] Ion Geophysical Corporation [Member] Goodwill [Member]
Business Acquisition [Line Items]
Business acquisition, cash paid	$ 14,500,000	$ 14,500,000
Business acquisition, credit		2,000,000
Number of product lines		2
Business acquisition, fair value consideration		$ 15,600,000	$ 600,000	$ 10,000,000	$ 3,600,000	$ 1,400,000