Selected Balance Sheet Information (Details) - USD ($) $ in Thousands	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2013
Accounts receivable, net:
Trade accounts	$ 39,103	$ 56,895	$ 54,962
Allowance for doubtful accounts	(1,034)	(319)	(319)
Accounts receivable, net	38,069	56,576	54,643
Inventories:
Finished goods	4,896	8,127	7,232
In process	1,845	1,317	2,131
Materials	39,147	45,708	45,502
Inventories	45,888	55,152	54,865
Other current assets:
Insurance policy benefit	716	733	733
Federal income taxes receivable	2,176	713	1,197
Prepaid expenses and other	1,992	1,648	1,358
Other current assets	4,884	3,094	3,288
Property, plant and equipment, net:
Property, plant and equipment, net	116,162	117,513	98,076
Other assets:
Investment in affiliate	2,805	3,217	3,684
Other	1,322	526	224
Other assets	4,127	3,743	3,908
Accrued liabilities:
Salaries and related	1,883	4,063	2,210
Benefits	3,864	5,001	5,538
Insurance obligations	1,730	1,590	1,598
Warranties	1,835	3,120	2,525	$ 1,888
Accrued Income Taxes, Current	475	536	362
Other taxes	1,117	1,240	1,097
Fair value of contingent consideration liability, current	407	1,375	890
Other	731	2,262	2,028
Accrued liabilities	12,042	19,187	16,248
Other liabilities:
Postretirement benefits	7,662	11,812	7,998
Fair value of contingent consideration liability, non current	2,499	3,631	2,457
Deferred income taxes	5,426	7,091	3,526
Uncertain tax positions	3,339	3,259	6,557
Other liabilities	18,926	25,793	20,538
Machinery and Equipment [Member]
Property, plant and equipment, net:
Property, Plant and Equipment, Gross	329	0	0
Land [Member]
Property, plant and equipment, net:
Property, Plant and Equipment, Gross	244	11	0
Building and Improvements [Member]
Property, plant and equipment, net:
Property, Plant and Equipment, Gross	1,595	1,522	0
Assets Held-for-sale [Member]
Property, plant and equipment, net:
Accumulated depreciation	(1,368)	(627)	0
Property, plant and equipment, net	800	906	0
Land [Member]
Property, plant and equipment, net:
Property, Plant and Equipment, Gross	3,054	3,246	2,077
Building and Improvements [Member]
Property, plant and equipment, net:
Property, Plant and Equipment, Gross	77,827	78,140	66,278
Machinery and Equipment [Member]
Property, plant and equipment, net:
Property, Plant and Equipment, Gross	140,995	131,766	114,345
Assets held for use [Member]
Property, plant and equipment, net:
Accumulated depreciation	(106,514)	(96,545)	(84,624)
Property, plant and equipment, net	115,362	116,607	98,076
Assets held for use [Member] | Assets Held-for-sale [Member]
Property, plant and equipment, net:
Property, plant and equipment, net	$ 116,162	$ 117,513	$ 98,076