DISPOSITIONS OF ASSETS (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Dec. 28, 2019	Feb. 01, 2019	Jan. 15, 2019	Jul. 31, 2015
Disposition of assets.
Escrow Deposit			$ 2,049,000		$ 200,000	$ 2,500,000
Write-off of deferred development costs	$ 111,000		$ 325,000
Revenue, expenses and pre-tax income reclassified to discontinued operations
Revenue		$ 4,058,000
Costs and expenses		(3,900,000)
Depreciation, depletion and amortization		(578,000)
Selling and administrative		(304,000)
Gain on sale of assets		6,508,000
Pre-tax income		5,784,000
The results of discontinued operations
Gain on sale of assets		6,508,000
Income tax benefit	0	(1,562,000)
Income from discontinued operations		4,222,000
Transit Mix Concrete | Discontinued operation
Disposition of assets.
Sale price				$ 27,129,000
Escrow Deposit	$ 111,000			$ 2,049,000
Revenue, expenses and pre-tax income reclassified to discontinued operations
Gain on sale of assets		6,508,000
The results of discontinued operations
Operating loss		(724,000)
Gain on sale of assets		6,508,000
Income tax benefit		(1,562,000)
Income from discontinued operations		$ 4,222,000