Property, Plant and Equipment - Summary of Property, Plant and Equipment (Detail) (USD $)	Apr. 30, 2015	Jan. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 12,061,000	$ 10,914,000
Less - accumulated depreciation	4,455,000	4,396,000
Property, plant and equipment, net	7,606,000	6,518,000
Land and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	473,000	473,000
Building and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,800,000	2,800,000
Furniture, Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,661,000	3,546,000
Trucks and Other Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,398,000	1,437,000
Construction Project Costs Of Variable Interest Entity [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 3,729,000	$ 2,658,000