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ACQUISITIONS - GFP (Details) - USD ($)		12 Months Ended
ACQUISITIONS - GFP (Details) - USD ($)	Jun. 03, 2019	Dec. 28, 2019	Dec. 29, 2018
ACQUISITIONS
Contingent liability		$ 58,000
Goodwill		5,932,000	$ 1,000,000
American Wheatley HVAC And Global Flow Products
ACQUISITIONS
Purchase price	$ 12,855,000
Estimated working capital adjustment	608,000
Consideration paid in cash	12,163,000
Contingent liability	4,300,000
Accrual For Earn Out Agreement Achievement Of Growth Targets	1,300,000
Trade receivables	1,916,000
Inventory	1,745,000
Property and equipment	2,530,000
Other assets	256,000
Intangibles	4,000,000
Goodwill	3,614,000
Retained liabilities	$ 1,205,000
American Wheatley HVAC And Global Flow Products \| Minimum
ACQUISITIONS
Earn out agreement, achievement of growth targets period	24 months
American Wheatley HVAC And Global Flow Products \| Maximum
ACQUISITIONS
Earn out agreement, achievement of growth targets period	36 months
Selling and administrative expense \| American Wheatley HVAC And Global Flow Products
ACQUISITIONS
Transaction costs		$ 1,229,000