Note 5 - Property, Plant and Equipment - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 28, 2024	Mar. 31, 2024	Dec. 30, 2023
Property, Plant and Equipment, Gross	$ 821,213	$ 772,622	$ 768,002
Less: accumulated depreciation	(496,908)	(467,606)	(460,288)
Property, plant and equipment, net	324,305	305,016	307,714
Land and Land Improvements [Member]
Property, Plant and Equipment, Gross	51,881	49,627	48,401
Building and Building Improvements [Member]
Property, Plant and Equipment, Gross	238,380	236,141	233,255
Machinery and Equipment [Member]
Property, Plant and Equipment, Gross	502,553	457,433	444,709
Office Furniture, Vehicles and Computer Software [Member]
Property, Plant and Equipment, Gross	15,555	14,971	13,934
Construction in Progress [Member]
Property, Plant and Equipment, Gross	$ 12,844	$ 14,450	$ 27,703