STOCKHOLDERS' EQUITY: - Directors Stock Award Plan (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
	May 27, 2022	Jun. 30, 2021	Sep. 30, 2024	Sep. 30, 2023
Parent Company (Grupo Mexico)
Activity in directors' stock award plan
Treasury stock balance at the end of the period (in shares)			64,810,241	69,798,524
Directors' Stock Award Plan
Share based Compensation Plan
Common shares received on election as director			1,600
Additional shares issued at each annual general meeting			1,600
Total SCC shares reserved for the plan			600,000	600,000
Period of extension of plan	5 years
Numbers of shares shall be granted quarterly and conditioned upon the attendance of each director to each Board meeting		400
Stock based compensation expense			$ 1.3	$ 0.7
Activity in directors' stock award plan
Total shares granted at the beginning of the period (in shares)			(428,800)	(416,800)
Granted (in shares)			(12,400)	(9,600)
Total shares granted at the end of the period (in shares)			(441,200)	(426,400)
Remaining shares reserved			158,800	173,600