COMMITMENTS AND CONTINGENCIES: - Guaymas sulfuric acid spill (Details)		3 Months Ended
	Jul. 09, 2019 m³	Mar. 31, 2020 country item m³
Climate change [Member]
Period of sustainability reports issued		10 years
Number of leading companies in sustainability | country		42
Marine Terminal in Guaymas
Volume of sulfuric acid discharged in the incident at Guaymas	3
Water volume at Guaymas bay		340,000,000
Number of times of renewal | item		4
Number of years of each renewal		2 years