Note 4 - Inventories (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Inventory, LIFO Reserve	$ 324,782	$ 302,440
Inventory, LIFO Reserve, Period Charge	$ 22,300	$ 131,600

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
-Topic 330
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.L)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480581/330-10-S99-1

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