Note 9 - Business Segment Reporting - Operations by Business Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Feb. 25, 2018	Feb. 26, 2017	Feb. 25, 2018	Feb. 26, 2017
Net sales	$ 149,323	$ 136,568	$ 409,137	$ 404,827
International sales	37,906	39,102	101,571	133,285
Gross profit	20,128	23,432	55,166	63,529
Net (loss) income	16,088	3,500	18,721	8,138
Depreciation and amortization	3,142	2,717	9,076	7,827
Dividend income	413	413	1,238	1,238
Interest income	87	8	161	15
Interest expense, net	531	400	1,415	1,432
Income tax (benefit) expense	(12,909)	1,556	(11,451)	4,138
Packaged Fresh Vegetables [Member]
Net sales	120,942	105,447	330,662	299,370
International sales	20,285	16,802	56,135	51,073
Gross profit	7,944	10,114	32,404	36,522
Net (loss) income	(2,545)	(2,492)	968	(419)
Depreciation and amortization	2,120	1,862	6,050	5,474
Dividend income	413	413	1,238	1,238
Interest income	32	8	61	15
Interest expense, net		(77)		594
Income tax (benefit) expense	(630)	(594)	372	(81)
Food Export [Member]
Net sales	4,414	7,276	25,982	56,316
International sales	4,414	7,276	25,982	56,316
Gross profit	318	558	1,628	3,436
Net (loss) income	(216)	(116)	(264)	812
Depreciation and amortization				3
Dividend income
Interest income
Interest expense, net
Income tax (benefit) expense	(61)	(33)	(75)	229
Biomaterials [Member]
Net sales	22,959	23,532	49,236	47,795
International sales	13,156	15,024	19,330	25,896
Gross profit	11,609	12,581	20,348	22,640
Net (loss) income	6,175	7,135	7,280	9,690
Depreciation and amortization	940	794	2,715	2,225
Dividend income
Interest income
Interest expense, net				13
Income tax (benefit) expense	1,763	2,031	2,110	2,769
Corporate Segment [Member]
Net sales	1,008	313	3,257	1,346
International sales	51		124
Gross profit	257	179	786	931
Net (loss) income	12,674	(1,027)	10,737	(1,945)
Depreciation and amortization	82	61	311	125
Dividend income			1,238
Interest income	55		100
Interest expense, net	531	477	1,415	825
Income tax (benefit) expense	$ (13,981)	$ 152	$ (13,858)	$ 1,221