COMMITMENTS AND CONTINGENCIES: - Environmental matters (Details) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2011 category person
Environmental costs
Environmental capital investment	$ 136.8	$ 77.6
Peru
Environmental costs
Environmental capital investment	3.5	5.5
Mexico
Environmental costs
Environmental capital investment	$ 133.2	$ 72.1
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