Selected Balance Sheet Information (Details) - USD ($)		Apr. 30, 2019	Feb. 01, 2019	Jan. 31, 2019	Apr. 30, 2018	Jan. 31, 2018
Accounts receivable, net:
Trade accounts		$ 62,539,000		$ 53,820,000
Unbilled receivables		6,033,000		1,391,000
Allowance for doubtful accounts		(780,000)		(739,000)
Accounts receivable, net		67,792,000		54,472,000
Inventories:
Finished goods		7,980,000		7,629,000
In process		1,219,000		1,103,000
Materials		48,843,000		45,344,000
Inventories		58,042,000		54,076,000
Other current assets:
Insurance policy benefit		318,000		336,000
Income tax receivable		1,418,000		1,045,000
Receivable from sale of investments		1,014,000		1,055,000
Prepaid Expense and other		4,513,000		6,300,000
Other current assets		7,263,000		8,736,000
Property, plant and equipment, net:
Property, plant and equipment, net		105,236,000		106,615,000
Other Assets (Noncurrent):
Equity investments		1,223,000		345,000
Operating Lease, Right-of-Use Asset		3,420,000	$ 3,807	0
Deferred Income Taxes, Noncurrent		60,000		16,000
Other		2,921,000		2,963,000
Other assets		7,624,000		3,324,000
Accrued liabilities:
Salaries and related		3,360,000		8,244,000
Benefits		5,097,000		4,751,000
Insurance obligations		1,856,000		1,963,000
Warranties		1,391,000		890,000	$ 1,097,000	$ 1,163,000
Income Taxes		831,000		328,000
Other taxes		940,000		2,434,000
Acquisition-related contingent consideration liability, current		1,306,000		1,796,000
Lease liability, current		1,978,000	1,446	0
Other		2,678,000		3,072,000
Accrued liabilities		19,437,000		23,478,000
Other liabilities:
Postretirement benefits		7,652,000		7,678,000
Acquisition-related contingent consideration liability, long-term		2,650,000		2,376,000
Lease liability, noncurrent		2,648,000	$ 2,571	0
Deferred income taxes		3,211,000		1,659,000
Uncertain tax positions		2,681,000		2,670,000
Other, Noncurrent		4,170,000		3,852,000
Other Liabilities, Noncurrent		23,012,000		18,235,000
Land [Member]
Property, plant and equipment, net:
Property, plant and equipment		3,234,000		3,234,000
Building and Building Improvements [Member]
Property, plant and equipment, net:
Property, plant and equipment		81,527,000		81,381,000
Machinery and Equipment [Member]
Property, plant and equipment, net:
Property, plant and equipment		156,745,000		155,463,000
Right-of-use Assets, Financing Leases [Member]
Property, plant and equipment, net:
Property, plant and equipment		665,000		0
Property, plant and equipment, Owned [Member]
Property, plant and equipment, net:
Accumulated depreciation				(133,724,000)
Property, plant and equipment, net	[1]			106,354,000
Property, plant and equipment, Owned and Right-of-Use Assets for financing lease [Member]
Property, plant and equipment, net:
Accumulated depreciation		(136,935,000)
Property, plant and equipment, net	[2]	105,236,000
Assets Held under Capital Leases [Member]
Property, plant and equipment, net:
Property, plant and equipment		0		510,000
Accumulated depreciation		$ 0		(249,000)
Assets owned or held under capital lease [Member]
Property, plant and equipment, net:
Property, plant and equipment, net				$ 106,615,000

[1] Hurricane recovery film sales for the three-month period ended April 30, 2019 and 2018, were $17 and $8,919, respectively.

[2] The amount of assets held for sale at April 30, 2019, and January 31, 2019, were not material.