Note 9 - Activity of Business Segments - Reconciliation of Total Segment Income to Total Consolidated Net Income (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 30, 2022	Mar. 31, 2021	Mar. 30, 2021
Consolidated net income	$ 1,522,000	$ 1,522,000	$ 3,719,000	$ 3,719,000
Provision for income taxes	452,000	$ 452,000	1,007,000	$ 1,007,000
Operating Segments [Member]
Consolidated net income	3,368,000		6,301,000
Operating Segments [Member] | Building Supply [Member]
Consolidated net income	1,667,000		1,551,000
Operating Segments [Member] | Disposable Protective Apparel [Member]
Consolidated net income	1,701,000		4,750,000
Corporate, Non-Segment [Member]
Consolidated net income	$ 1,394,000		$ 1,575,000