Selected Balance Sheet Information (Details) - USD ($) $ in Thousands	Apr. 30, 2017	Jan. 31, 2017	Apr. 30, 2016	Jan. 31, 2016
Accounts receivable, net:
Trade accounts	$ 52,513	$ 43,834	$ 42,041
Allowance for doubtful accounts	(896)	(691)	(1,028)
Accounts receivable, net	51,617	43,143	41,013
Inventories:
Finished goods	5,385	5,438	4,570
In process	1,673	2,288	1,751
Materials	42,809	34,610	40,580
Inventories	49,867	42,336	46,901
Other current assets:
Insurance policy benefit	739	802	742
Federal tax receivable	206	604	1,265
Receivable from sale of business	14	28	205
Prepaid Expense and other	2,297	1,255	2,677
Other current assets	3,256	2,689	4,889
Property, plant and equipment, net:
Property, plant and equipment, net	106,194	106,324	113,374
Other Assets (Noncurrent):
Equity investments	2,180	2,371	2,813
Deferred Tax Assets, Net, Noncurrent	17	18	25
Other	1,245	1,283	1,407
Other assets	3,442	3,672	4,245
Accrued liabilities:
Salaries and related	2,833	6,286	1,874
Benefits	4,090	3,960	3,945
Insurance obligations	2,532	2,400	1,893
Warranties	2,405	1,547	2,316	$ 1,835
Income Taxes	6,363	498	708
Other taxes	1,089	1,540	1,008
Acquisition-related contingent consideration liability, Current	501	445	364
Other	2,051	1,379	595
Accrued liabilities	21,864	18,055	12,703
Other liabilities:
Postretirement benefits	8,076	8,054	7,678
Acquisition-related contingent consideration liability, Noncurrent	1,238	1,397	1,642
Deferred income taxes	636	1,421	2,120
Uncertain tax positions	2,601	2,610	2,999
Liabilities, Noncurrent	175	214	0
Other liabilities	12,726	13,696	14,439
Land [Member]
Property, plant and equipment, net:
Property, plant and equipment	0	0	244
Building and Building Improvements [Member]
Property, plant and equipment, net:
Property, plant and equipment	0	0	1,595
Machinery and Equipment [Member]
Property, plant and equipment, net:
Property, plant and equipment	0	0	329
Assets Held-for-sale [Member]
Property, plant and equipment, net:
Accumulated depreciation	0	0	(1,368)
Property, plant and equipment, net	0	0	800
Land [Member]
Property, plant and equipment, net:
Property, plant and equipment	3,054	3,054	3,054
Building and Building Improvements [Member]
Property, plant and equipment, net:
Property, plant and equipment	79,676	77,817	77,871
Machinery and Equipment [Member]
Property, plant and equipment, net:
Property, plant and equipment	143,405	142,471	141,274
Assets held for use [Member]
Property, plant and equipment, net:
Accumulated depreciation	(119,941)	(117,018)	(109,625)
Property, plant and equipment, net	106,194	106,324	112,574
Assets held for use [Member] | Assets Held-for-sale [Member]
Property, plant and equipment, net:
Property, plant and equipment, net	$ 106,194	$ 106,324	$ 113,374