Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Cash flows from operating activities:
Net income	$ 17,051	$ 24,321	$ 4,729
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	34,939	28,774	22,717
Stock-based compensation	1,586	1,331	1,099
Provision for doubtful accounts, net of charge offs	(636)	1,709	1,795
Gain from bargain purchase in business combination			(1,304)
Provision for inventory obsolescence	163	173	94
Gross profit from sale of lease pool equipment	(5,369)	(4,923)	(1,340)
Excess tax expense (benefit) from exercise of non-qualified stock options and restricted shares	(420)	(778)	5
Deferred tax benefit	(4,450)	(285)	(230)
Changes in non-current income taxes payable	(5,059)	597	224
Changes in:
Trade accounts and contracts receivable	13,331	(16,687)	(2,019)
Inventories	718	(2,614)	727
Income taxes payable and receivable	(6,718)	2,532	1,001
Contract revenues in excess of billings			573
Prepaid foreign income tax	3,519	(440)	(318)
Accounts payable, accrued expenses and other current liabilities	(4,091)	2,683	1,964
Prepaids and other, net	(307)	(435)	420
Net cash provided by operating activities	44,257	35,958	30,137
Cash flows from investing activities:
Purchases of seismic equipment held for lease	(44,694)	(62,142)	(32,736)
Purchases of property and equipment	(965)	(1,525)	(383)
Sales of used lease pool equipment	11,412	6,503	2,470
Acquisition of AES, net of cash acquired			(2,100)
Payment for earn-out provision	(450)	(148)
Net cash used in investing activities	(34,697)	(57,312)	(32,749)
Cash flows from financing activities:
Net (payments on) proceeds from revolving line of credit	(8,550)	(9,100)	6,300
Proceeds from equipment notes	147	37	3,672
Payments on borrowings	(1,532)	(3,308)	(719)
Net purchases of short-term investment	(689)	(101)	684
Proceeds from issuance of common stock upon exercise of options	329	2,809	396
Net proceeds from public offering of common stock		31,028
Excess tax benefit (expense) from exercise of non-qualified stock options	420	778	(5)
Net cash (used in) provided by financing activities	(9,875)	22,143	10,328
Effect of changes in foreign exchange rates on cash and cash equivalents	178	(149)	801
Net (decrease) increase in cash and cash equivalents	(137)	640	8,517
Cash and cash equivalents, beginning of year	15,287	14,647	6,130
Cash and cash equivalents, end of year	$ 15,150	$ 15,287	$ 14,647