Note 2 - Discontinued Operations (Details Textual) - USD ($)		3 Months Ended			9 Months Ended
	Jul. 13, 2018	Dec. 26, 2020	Dec. 28, 2019	Jun. 29, 2019	Dec. 26, 2020	Dec. 28, 2019
Pension Termination [Member]
Disposal Group, Including Discontinued Operation, Restructuriing Charge			$ 902,000			$ 902,000
Modesto Facility [Member] | Discontinued Operations, Disposed of by Sale [Member]
Proceeds from Divestiture of Businesses, Net of Cash Divested, Total	$ 63,326,000
Disposal Group, Including Discontinued Operation, Revenue, Percent				15.00%
Disposal Group, Including Discontinued Operation, Restructuriing Charge		$ 0	$ (902,000)		$ 0	$ (902,000)