Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Oct. 31, 2011	Oct. 31, 2010
Cash flows from operating activities:
Net income	$ 14,156	$ 2,975
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	21,038	16,586
Stock-based compensation	1,133	941
Gain from bargain purchase in business combination		(1,304)
Provisions for doubtful accounts	1,281	797
Provision for inventory obsolescence	73	63
Gross profit from sale of lease pool equipment	(2,380)	(864)
Excess tax benefit from exercise of non-qualified stock options and restricted shares	(394)	(3)
Deferred tax benefit	(763)	(1,335)
Changes in non-current income taxes payable	822	144
Changes in working capital items, net of effects from business combination:
Accounts receivable	(10,794)	609
Contracts receivable	2,590	(2,376)
Inventories	(972)	833
Prepaid expenses and other current assets	(625)	(952)
Income taxes receivable and payable	1,167	1,833
Costs incurred and estimated profit in excess of billings on uncompleted contract		573
Prepaid foreign income tax	(419)	(221)
Accounts payable, accrued expenses, other current liabilities and deferred revenue	2,447	1,996
Net cash provided by operating activities	28,360	20,295
Cash flows from investing activities:
Purchases of seismic equipment held for lease	(40,957)	(16,049)
Purchases of property and equipment	(1,084)	(262)
Sale of used lease pool equipment	3,103	1,498
Payment for earn-out provision (Note 4)	(148)
Acquisition of AES, net of cash acquired		(2,100)
Net cash used in investing activities	(39,086)	(16,913)
Cash flows from financing activities:
Net payments on line of credit	(17,700)	(4,250)
Proceeds from equipment notes	37	3,672
Payments on borrowings	(2,647)	(122)
Net purchases of short-term investments	(101)	(15)
Proceeds from issuance of common stock upon exercise of options	788	244
Net proceeds from public offering of common stock (Note 9)	31,028
Excess tax benefit from exercise of non-qualified stock options and restricted shares	394	3
Net cash provided by (used in) financing activities	11,799	(468)
Effect of changes in foreign exchange rates on cash and cash equivalents	186	477
Net change in cash and cash equivalents	1,259	3,391
Cash and cash equivalents, beginning of period	14,647	6,130
Cash and cash equivalents, end of period	15,906	9,521
Supplemental cash flow information:
Interest paid	574	465
Income taxes paid	4,206	1,716
Purchases of seismic equipment held for lease in accounts payable at end of period	$ 18,484	$ 9,621