COMMITMENTS AND CONTINGENCIES: - Environmental matters (Details) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2011 category person
Environmental costs
Environmental capital investment	$ 42.5	$ 60.6
Peru
Environmental costs
Environmental capital investment	7.1	2.9
Mexico
Environmental costs
Environmental capital investment	$ 35.4	$ 57.7
Number of categories of collective actions | category			3
Minimum number of people claiming injury due to collective action initiative in Civil Federal Procedures Code (CFPC) | person			30