Note 9 - Plant Restructuring (Details Textual) - USD ($)	3 Months Ended
	Sep. 28, 2019	Jun. 29, 2019	Sep. 29, 2018	Jun. 30, 2018
Closing of Midwest and Northwest Plants [Member]
Restructuring Charges, Total	$ 1,146,000	$ 4,806,000
Restructuring Credit For Reduced Lease Liability	1,875,000
Closing of Midwest and Northwest Plants [Member] | Lease Impairments [Member]
Restructuring Charges, Total	2,230,000	2,245,000
Closing of Midwest and Northwest Plants [Member] | Equipment Moves [Member]
Restructuring Charges, Total	405,000	1,975,000
Closing of Midwest and Northwest Plants [Member] | Employee Severance [Member]
Restructuring Charges, Total	$ 386,000	$ 586,000
Closing of East and Northwest Plants [Member]
Restructuring Charges, Total			$ 845,000
Closing of East and Northwest Plants [Member] | Employee Severance [Member]
Restructuring Charges, Total			841,000
Closing of East and Northwest Plants [Member] | Other Restructuring [Member]
Restructuring Charges, Total			$ 4,000
Closing of Northwest Plant [Member]
Restructuring Charges, Total				$ 38,000
Closing of Northwest Plant [Member] | Employee Severance [Member]
Restructuring Charges, Total				110,000
Closing of Northwest Plant [Member] | Other Restructuring [Member]
Restructuring Charges, Total				20,000
Closing of Northwest Plant [Member] | Impairment of Long-Lived Assets [Member]
Restructuring Charges, Total				$ 92,000