Income Taxes (Significant Components of the Company's Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Current deferred tax assets:
Accounts receivable	$ 355	$ 194	$ 111
Inventories	602	873	583
Accrued vacation	836	940	1,032
Insurance obligations	350	271	276
Accrued benefit liabilities	99	261	291
Warranty obligations	670	1,225	898
Other accrued liabilities	198	194	181
Deferred tax assets, net, current	3,110	3,958	3,372
Non-current deferred tax assets (liabilities):
Postretirement benefits	2,797	4,243	2,799
Depreciation and amortization	(9,886)	(16,099)	(11,522)
Uncertain tax positions	896	1,002	2,219
Share-based compensation	3,613	4,410	3,196
Other	(667)	(647)	(218)
Deferred tax liabilities, net, non-current	(3,247)	(7,091)	(3,526)
Net deferred tax (liability)	$ (137)	$ (3,133)	$ (154)