Note 16 - Plant Restructuring - Restructuring Reserve (Details) - USD ($) $ in Thousands	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Balance	$ 226
Charge to expense	7,046	11,657
Cash payments/write offs	(7,070)	(11,431)
Balance	202	226
Employee Severance [Member]
Balance	225
Charge to expense	1,229	1,508
Cash payments/write offs	(1,252)	(1,283)
Balance	202	225
Other Restructuring [Member]
Balance	1
Charge to expense	5,817	10,149
Cash payments/write offs	(5,818)	(10,148)
Balance		$ 1

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration