Segment Reporting - Financial Information by Business Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Segment Reporting Information [Line Items]
Fixed assets, net	$ 129,573				$ 119,608				$ 129,573	$ 119,608	$ 120,377
Intangible assets, net	3,201				3,989				3,201	3,989	4,696
Goodwill	4,320				4,320				4,320	4,320	4,320
Total Assets	205,419				190,407				205,419	190,407	198,229
Revenues	23,647	20,275	20,895	27,291	28,401	18,574	23,080	34,630	92,108	104,685	112,834
Interest income (expense), net									(10)	11	(396)
Income before taxes									6,026	13,524	34,330
Capital expenditures									44,058	45,659	63,667
Depreciation and amortization expense									31,037	34,939	28,774
Equipment Leasing [Member]
Segment Reporting Information [Line Items]
Fixed assets, net	128,847				118,801				128,847	118,801	119,824
Intangible assets, net	1,529				2,111				1,529	2,111	2,511
Goodwill
Total Assets	183,911				171,971				183,911	171,971	175,930
Revenues									67,022	73,516	84,428
Interest income (expense), net									(12)	11	(397)
Income before taxes									1,087	2,865	24,081
Capital expenditures									43,663	45,181	63,198
Depreciation and amortization expense									30,353	34,320	28,215
Seamap [Member]
Segment Reporting Information [Line Items]
Fixed assets, net	726				807				726	807	553
Intangible assets, net	1,672				1,878				1,672	1,878	2,185
Goodwill	4,320				4,320				4,320	4,320	4,320
Total Assets	21,814				18,578				21,814	18,578	22,630
Revenues									25,252	32,210	28,703
Interest income (expense), net									2		1
Income before taxes									4,720	10,835	10,195
Capital expenditures									395	478	469
Depreciation and amortization expense									$ 684	$ 619	$ 559