Segment Reporting - Financial Information by Business Segment (Assets) (Detail) - USD ($) $ in Thousands	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Segment Reporting Information [Line Items]
Fixed assets, net	$ 22,900	$ 43,838	$ 73,516
Intangible assets, net	8,015	9,012	10,466
Goodwill	2,531	3,997	4,155
Total Assets	73,679	94,714	134,759
Marine Technology Products
Segment Reporting Information [Line Items]
Fixed assets, net	3,790	4,036	4,278
Intangible assets, net	8,015	9,012	10,466
Goodwill	2,531	3,997	4,155
Total Assets	35,879	37,294	39,059
Equipment Leasing
Segment Reporting Information [Line Items]
Fixed assets, net	19,161	39,926	69,238
Intangible assets, net	0	0	0
Goodwill	0	0	0
Total Assets	$ 37,850	$ 57,544	$ 95,932