Note 10 - Retirement Plans - Amounts Recognized in Accumulated Other Comprehensive (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Prior service cost	$ (258)	$ (349)
Net loss	(26,265)	(105,866)
Accumulated other comprehensive pre-tax loss	$ (26,523)	$ (106,215)

Amount, before tax, of accumulated other comprehensive income (loss) for transition asset (obligation) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (j)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (k)
-URI http://asc.fasb.org/extlink&oid=124509347&loc=SL7669646-108580

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=124509347&loc=SL7669686-108580

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant