Note 4 - Inventories (Details Textual) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Oct. 02, 2021	Sep. 26, 2020	Oct. 02, 2021	Sep. 26, 2020	Mar. 31, 2021
Inventory, LIFO Reserve	$ 140,311	$ 144,655	$ 140,311	$ 144,655	$ 128,672
Inventory, LIFO Reserve, Period Charge	$ 8,800	$ 2,500	$ 11,600	$ 400

The change in the inventory reserve representing the cumulative difference in cost between the first in, first out and the last in, first out inventory valuation methods, which change has been reflected in the statement of income during the period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.6b)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-Subparagraph (SX 210.5-02.6a)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 330
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.L)
-URI http://asc.fasb.org/extlink&oid=27011343&loc=d3e99989-122729

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration