Note 10 - Retirement Plans - Amounts Recognized in Accumulated Other Comprehensive (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Prior service cost	$ (349)	$ (587)
Net loss	(105,866)	(24,305)
Accumulated other comprehensive pre-tax loss	$ (106,215)	$ (24,892)

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=118255775&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
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-URI http://asc.fasb.org/extlink&oid=121641772&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=121641772&loc=SL7669686-108580

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant