Selected Balance Sheet Information (Details) - USD ($) $ in Thousands	Apr. 30, 2018	Jan. 31, 2018	Apr. 30, 2017	Jan. 31, 2017
Accounts receivable, net:
Trade accounts	$ 65,723	$ 57,063
Unbilled receivables	2,031	2,447
Allowance for doubtful accounts	(942)	(978)
Accounts receivable, net	66,812	58,532
Inventories:
Finished goods	7,008	8,054
In process	995	961
Materials	47,159	46,336
Inventories	55,162	55,351
Other current assets:
Insurance policy benefit	207	759
Income tax receivable	10	1,397
Prepaid Expense and other	4,266	3,705
Other current assets	4,483	5,861
Property, plant and equipment, net:
Property, plant and equipment, net	107,037	106,280
Other Assets (Noncurrent):
Equity investments	96	1,955
Receivable from sale of investments	1,167	0
Deferred Tax Assets, Net, Noncurrent	21	19
Other	2,663	976
Other assets	3,947	2,950
Accrued liabilities:
Salaries and related	3,309	9,409
Benefits	4,180	4,225
Insurance obligations	2,215	1,992
Warranties	1,097	1,163	$ 2,405	$ 1,547
Income Taxes	4,126	226
Other taxes	905	1,880
Acquisition-related contingent consideration liability, current	1,483	1,036
Other	2,947	2,015
Accrued liabilities	20,262	21,946
Other liabilities:
Postretirement benefits	8,228	8,264
Acquisition-related contingent consideration liability, long-term	1,420	2,010
Deferred income taxes	320	615
Uncertain tax positions	2,635	2,634
Liabilities, Noncurrent	3,450	272
Other liabilities	16,053	13,795
Land [Member]
Property, plant and equipment, net:
Property, plant and equipment	3,234	3,234
Building and Building Improvements [Member]
Property, plant and equipment, net:
Property, plant and equipment	80,244	80,299
Machinery and Equipment [Member]
Property, plant and equipment, net:
Property, plant and equipment	153,489	149,847
Property, plant and equipment, Owned [Member]
Property, plant and equipment, net:
Accumulated depreciation	(130,337)	(127,523)
Property, plant and equipment, net	106,630	105,857
Assets Held under Capital Leases [Member]
Property, plant and equipment, net:
Property, plant and equipment	521	488
Accumulated depreciation	(114)	(65)
Assets owned or held under capital lease [Member]
Property, plant and equipment, net:
Property, plant and equipment, net	$ 107,037	$ 106,280