Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2010
Cash flows from operating activities:
Net income	$ 24,321	$ 4,729	$ 520
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	28,774	22,717	18,740
Stock-based compensation	1,331	1,099	1,401
Provision for doubtful accounts	1,709	1,795	1,378
Gain from bargain purchase in business combination		(1,304)
Provision for inventory obsolescence	173	94	(48)
Gross profit from sale of lease pool equipment	(4,923)	(1,340)	(755)
Excess tax expense (benefit) from exercise of non-qualified stock options	(778)	5	(45)
Benefit for deferred income taxes	(285)	(230)	(120)
Non-current income taxes payable	597	224	270
Changes in:
Trade accounts and contracts receivable	(16,687)	(2,019)	(4,995)
Inventories	(2,614)	727	(754)
Income taxes payable and receivable	2,532	1,001	715
Contract revenues in excess of billings		573	1,704
Prepaid foreign income tax	(440)	(318)	(2,620)
Accounts payable, accrued expenses and other current liabilities	2,683	1,964	(836)
Prepaids and other, net	(435)	420	(470)
Net cash provided by operating activities	35,958	30,137	14,085
Cash flows from investing activities:
Purchases of seismic equipment held for lease	(62,142)	(32,736)	(26,684)
Purchases of property and equipment	(1,525)	(383)	(502)
Sales of used lease pool equipment	6,503	2,470	3,321
Acquisition of AES, net of cash acquired		(2,100)
Payment for earn-out provision (Note 3)	(148)
Net cash used in investing activities	(57,312)	(32,749)	(23,865)
Cash flows from financing activities:
Net (payments) proceeds from revolving line of credit	(9,100)	6,300	9,400
Proceeds from equipment notes	37	3,672	414
Payments on borrowings	(3,308)	(719)
Redemption (purchase) of short-term investment	(101)	684	744
Proceeds from issuance of common stock upon exercise of options, net of shares surrendered during exercises	2,809	396	(17)
Net proceeds from public offering of common stock	31,028
Excess tax (expense) benefit from exercise of non-qualified stock options	778	(5)	45
Net cash provided by financing activities	22,143	10,328	10,586
Effect of changes in foreign exchange rates on cash and cash equivalents	(149)	801	261
Net increase in cash and cash equivalents	640	8,517	1,067
Cash and cash equivalents, beginning of year	14,647	6,130	5,063
Cash and cash equivalents, end of year	$ 15,287	$ 14,647	$ 6,130