Note 10 - Plant Restructuring (Details Textual) - USD ($)	9 Months Ended
	Dec. 26, 2020	Dec. 28, 2019
Closing of Northeast Plant [Member]
Restructuring Charges, Total	$ 169,000	$ 6,745,000
Closing of Northeast Plant [Member] | Employee Severance [Member]
Restructuring Charges, Total	227,000	1,000,000
Closing of Northeast Plant [Member] | Lease Impairments [Member]
Restructuring Charges, Total	44,000	5,266,000
Closing of Northeast Plant [Member] | Former Grower Payment [Member]
Restructuring Credits, Total	$ 102,000
Closing of Northeast Plant [Member] | Equipment Moves [Member]
Restructuring Charges, Total		2,354,000
Closing of Midwest and Northwest Plants [Member] | Lease Impairments [Member]
Restructuring Credits, Total		$ 1,875,000