Selected Balance Sheet Information (Details) - USD ($) $ in Thousands	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Accounts receivable, net:
Trade accounts	$ 43,834	$ 39,103	$ 56,895
Allowance for doubtful accounts	(691)	(1,034)	(319)
Accounts receivable, net	43,143	38,069	56,576
Inventories:
Finished goods	5,438	4,896	8,127
In process	2,288	1,845	1,317
Materials	34,610	39,098	45,708
Inventories	42,336	45,839	55,152
Other current assets:
Insurance policy benefit	802	716	733
Federal income taxes receivable	604	1,721	713
Prepaid expenses and other	1,283	1,992	1,648
Other current assets	2,689	4,429	3,094
Property, plant and equipment, net:
Property, plant and equipment, net	106,324	115,704	117,513
Other assets:
Equity Investments	2,371	2,805	3,217
Deferred income taxes	18	0	0
Other	1,283	1,322	526
Other assets	3,672	4,127	3,743
Accrued liabilities:
Salaries and related	6,286	1,883	4,063
Benefits	3,960	3,864	5,001
Insurance obligations	2,400	1,730	1,590
Warranties	1,547	1,835	3,120	$ 2,525
Accrued Income Taxes, Current	498	475	536
Other taxes	1,540	1,117	1,240
Fair value of contingent consideration liability, current	445	407	1,375
Other	1,379	731	2,262
Accrued liabilities	18,055	12,042	19,187
Other liabilities:
Postretirement benefits	8,054	7,662	11,812
Fair value of contingent consideration liability, non current	1,397	1,732	3,631
Deferred income taxes	1,421	3,247	7,091
Uncertain tax positions	2,610	2,999	3,259
Other	214	0	0
Other liabilities	13,696	15,640	25,793
Land [Member]
Property, plant and equipment, net:
Property, Plant and Equipment, Gross	0	244	11
Building and Improvements [Member]
Property, plant and equipment, net:
Property, Plant and Equipment, Gross	0	1,595	1,522
Machinery and Equipment [Member]
Property, plant and equipment, net:
Property, Plant and Equipment, Gross	0	329	0
Assets Held-for-sale [Member]
Property, plant and equipment, net:
Accumulated depreciation	0	(1,368)	(627)
Property, plant and equipment, net	0	800	906
Land [Member]
Property, plant and equipment, net:
Property, Plant and Equipment, Gross	3,054	3,054	3,246
Building and Improvements [Member]
Property, plant and equipment, net:
Property, Plant and Equipment, Gross	77,817	77,797	78,140
Machinery and Equipment [Member]
Property, plant and equipment, net:
Property, Plant and Equipment, Gross	142,471	140,472	131,766
Assets held for use [Member]
Property, plant and equipment, net:
Accumulated depreciation	(117,018)	(106,419)	(96,545)
Property, plant and equipment, net	106,324	114,904	116,607
Assets held for use [Member] | Assets Held-for-sale [Member]
Property, plant and equipment, net:
Property, plant and equipment, net	$ 106,324	$ 115,704	$ 117,513