Note 4 - Revenue Recognition - Segment Revenue Disaggregated by Product Category Groups (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Net sales	$ 390,294	$ 370,002	$ 678,459	$ 634,927
Canned Vegetables [Member]
Net sales	302,300	272,800	523,300	460,100
Frozen [Member]
Net sales	31,000	41,000	49,000	59,100
Fruit [Member]
Net sales	23,900	26,900	42,700	49,500
Chip Products [Member]
Net sales	3,100	3,100	5,400	6,000
Prepared Foods [Member]
Net sales	24,200	23,600	48,400	53,500
Manufactured Product, Other [Member]
Net sales	$ 5,800	$ 2,600	$ 9,700	$ 6,700