Note 5 - Property, Plant and Equipment - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 27, 2025	Mar. 31, 2025	Dec. 28, 2024
Property, Plant and Equipment, Gross	$ 850,572	$ 825,052	$ 821,213
Less: accumulated depreciation	(528,938)	(500,284)	(496,908)
Property, plant and equipment, net	321,634	324,768	324,305
Land and Land Improvements [Member]
Property, Plant and Equipment, Gross	54,005	52,339	51,881
Building and Building Improvements [Member]
Property, Plant and Equipment, Gross	240,849	238,709	238,380
Machinery and Equipment [Member]
Property, Plant and Equipment, Gross	524,535	502,223	502,553
Office Furniture, Vehicles and Computer Software [Member]
Property, Plant and Equipment, Gross	16,239	15,604	15,555
Construction in Progress [Member]
Property, Plant and Equipment, Gross	$ 14,944	$ 16,177	$ 12,844