Note 10 - Other Operating Income and Expense (Details Textual) - Other Operating Income (Expense) [Member] - USD ($)	9 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property	$ 3,139,000
Partial Closure of Midwest Plant [Member]
Gain (Loss) On Sale of Plant	3,742,000
Closing of Northwest Plant [Member]
Gain (Loss) On Sale of Plant	$ 1,737,000
Closed Plant in the Midwest [Member]
Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property		$ 3,920,000