Selected Balance Sheet Information (Details) - USD ($) $ in Thousands	Apr. 30, 2016	Jan. 31, 2016	Apr. 30, 2015	Jan. 31, 2015
Accounts receivable, net:
Trade accounts	$ 42,041	$ 39,103	$ 45,686
Allowance for doubtful accounts	(1,028)	(1,034)	(453)
Accounts receivable, net	41,013	38,069	45,233
Inventories:
Finished goods	4,570	4,896	9,127
In process	1,751	1,845	2,533
Materials	40,580	39,098	47,321
Inventories	46,901	45,839	58,981
Other current assets:
Insurance policy benefit	742	716	683
Federal tax receivable	1,265	1,721	0
Receivable from sale of business	205	255	789
Prepaid Expense and other	2,677	1,737	4,889
Other current assets	4,889	4,429	6,361
Property, plant and equipment, net:
Property, plant and equipment, net	113,374	115,704	118,429
Other Assets (Noncurrent):
Equity investments	2,813	2,805	3,095
Deferred Tax Assets, Net, Noncurrent	25	0	0
Other	1,407	1,322	1,264
Other assets	4,245	4,127	4,359
Accrued liabilities:
Salaries and related	1,874	1,883	3,035
Benefits	3,945	3,864	4,655
Insurance obligations	1,893	1,730	1,629
Warranties	2,316	1,835	2,285	$ 3,120
Income Taxes	708	475	1,824
Other taxes	1,008	1,117	936
Acquisition-related contingent consideration liability, Current	364	407	938
Other	595	731	1,433
Accrued liabilities	12,703	12,042	16,735
Other liabilities:
Postretirement benefits	7,678	7,662	11,976
Acquisition-related contingent consideration liability, Noncurrent	1,642	1,732	3,046
Deferred income taxes	2,120	3,247	7,278
Uncertain tax positions	2,999	2,999	3,281
Other liabilities	14,439	15,640	25,581
Land [Member]
Property, plant and equipment, net:
Property, plant and equipment	244	244	11
Building and Building Improvements [Member]
Property, plant and equipment, net:
Property, plant and equipment	1,595	1,595	1,522
Machinery and Equipment [Member]
Property, plant and equipment, net:
Property, plant and equipment	329	329	0
Assets Held-for-sale [Member]
Property, plant and equipment, net:
Accumulated depreciation	(1,368)	(1,368)	(627)
Property, plant and equipment, net	800	800	906
Land [Member]
Property, plant and equipment, net:
Property, plant and equipment	3,054	3,054	3,246
Building and Building Improvements [Member]
Property, plant and equipment, net:
Property, plant and equipment	77,901	77,827	78,661
Machinery and Equipment [Member]
Property, plant and equipment, net:
Property, plant and equipment	141,798	140,996	135,154
Assets held for use [Member]
Property, plant and equipment, net:
Accumulated depreciation	(109,625)	(106,419)	(99,538)
Accumulated Impairment, Property, Plant and Equipment	(554)	(554)	0
Property, plant and equipment, net	112,574	114,904	117,523
Assets held for use [Member] | Assets Held-for-sale [Member]
Property, plant and equipment, net:
Property, plant and equipment, net	$ 113,374	$ 115,704	$ 118,429