Note 5 - Inventories (Details Textual) - USD ($)	3 Months Ended	9 Months Ended
Dec. 29, 2018	Dec. 30, 2017	Dec. 29, 2018	Dec. 30, 2017
Inventory, LIFO Reserve	$ 160,727,000	$ 152,091,000	$ 160,727,000	$ 152,091,000
Inventory, LIFO Reserve, Period Charge	$ 25,776,000	994,000	15,722,000	18,835,000
Cost of Sales [Member]
Inventory, LIFO Reserve, Period Charge			39,933,000
Modesto Facility [Member] \| Discontinued Operations, Disposed of by Sale [Member]
Inventory, LIFO Reserve, Period Charge		$ (274,000)		$ (928,000)
Effect of LIFO Inventory Liquidation on Income			$ 24,211,000

The effect of liquidating LIFO (last in first out) inventory layers on income.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 330
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SAB Topic 11.F)
-URI http://asc.fasb.org/extlink&oid=27011343&loc=d3e100079-122729

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Amount by which inventory stated at last-in first-out (LIFO) is less than (in excess of) inventory stated at other inventory cost methods.

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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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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