ASSET RETIREMENT OBLIGATIONS (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) a property item	Sep. 30, 2019 USD ($)
Asset Retirement Obligations [Line Items]
Reclamation activities	$ 2,459	$ 2,684	$ 11,047	$ 9,650
California [Member]
Asset Retirement Obligations [Line Items]
Reclamation activities			$ 2,358	$ 2,403
Adjacent aggregates sites | property			2
Property, acres | a			90
Number of aggregates locations | item			3