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Balance Sheet - Additional Information (Detail) (USD $)
6 Months Ended 12 Months Ended 0 Months Ended 6 Months Ended
Jul. 31, 2014
Customer
Jan. 31, 2014
Customer
May 31, 2014
Seamap Pte Ltd [Member]
Ion Geophysical Corporation [Member]
Product_Lines
May 31, 2014
Inventory [Member]
Seamap Pte Ltd [Member]
Ion Geophysical Corporation [Member]
Jul. 31, 2014
Minimum [Member]
Jul. 31, 2014
Maximum [Member]
Balance Sheet [Line Items]            
Contracts and notes receivable $ 904,000 $ 1,005,000        
Contracts receivable, Interest rate 8.60% 8.60%        
Number of customers due 3 3        
Contracts receivable repayment term         1 month 2 months
Allowance for contract receivable 0 0        
Business acquisition, fair value consideration     $ 15,600,000 $ 3,600,000    
Number of product lines     2