Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
	Apr. 30, 2013	Apr. 30, 2012
Cash flows from operating activities:
Net income	$ 6,307,000	$ 8,456,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	7,826,000	8,757,000
Stock-based compensation	266,000	194,000
Provision for inventory obsolescence	58,000	60,000
Gross profit from sale of lease pool equipment	(498,000)	(928,000)
Excess tax benefit from exercise of non-qualified stock options and restricted shares	(56,000)	(350,000)
Deferred tax benefit (provision)	259,000	(1,257,000)
Changes in working capital items:
Accounts receivable	(5,665,000)	4,357,000
Contracts and notes receivable	688,000	(632,000)
Inventories	(1,345,000)	165,000
Prepaid expenses and other current assets	(1,578,000)	(422,000)
Income taxes receivable and payable	(46,000)	532,000
Prepaid foreign income tax		(236,000)
Accounts payable, accrued expenses, other current liabilities and deferred revenue	2,174,000	(832,000)
Net cash provided by operating activities	8,390,000	17,864,000
Cash flows from investing activities:
Purchases of seismic equipment held for lease	(4,945,000)	(23,812,000)
Purchases of property and equipment	(161,000)	(146,000)
Sale of used lease pool equipment	900,000	2,332,000
Net cash used in investing activities	(4,206,000)	(21,626,000)
Cash flows from financing activities:
Net (payments on) proceeds from revolving line of credit	(2,000,000)	6,650,000
Payments on borrowings	(39,000)	(1,465,000)
Net purchases of short-term investments	3,000
Proceeds from issuance of common stock upon exercise of options	60,000	96,000
Purchase of treasury stock	(1,527,000)
Excess tax benefit from exercise of non-qualified stock options and restricted shares	56,000	350,000
Net cash (used in) provided by financing activities	(3,447,000)	5,631,000
Effect of changes in foreign exchange rates on cash and cash equivalents	657,000	276,000
Net change in cash and cash equivalents	1,394,000	2,145,000
Cash and cash equivalents, beginning of period	15,150,000	15,287,000
Cash and cash equivalents, end of period	16,544,000	17,432,000
Supplemental cash flow information:
Interest paid	66,000	167,000
Income taxes paid	1,379,000	3,821,000
Purchases of seismic equipment held for lease in accounts payable at end of period	$ 995,000	$ 2,000,000