SEGMENT AND RELATED INFORMATION: (Details) (USD $)	3 Months Ended
	Mar. 31, 2015 segment	Mar. 31, 2014	Dec. 31, 2014
SEGMENT AND RELATED INFORMATION:
Number of reportable segments	3
Financial information relating to segments
Net sales	$ 1,274,800,000	$ 1,354,400,000
Cost of sales (exclusive of depreciation, amortization and depletion)	679,822,000	641,894,000
Selling, general and administrative	24,869,000	24,498,000
Depreciation, amortization and depletion	116,963,000	110,453,000
Exploration	10,288,000	14,611,000
Environmental reclamation	5,928,000
Operating income	436,937,000	562,927,000
Interest, net	(23,100,000)	(36,000,000)
Other income (expense)	(3,764,000)	(4,206,000)
Income taxes	(129,193,000)	(204,162,000)
Equity earnings of affiliate	2,760,000	6,038,000
Non-controlling interest	(1,257,000)	(1,208,000)
Net income attributable to SCC	282,430,000	323,389,000
Capital investment	245,800,000	336,900,000
Property, net	7,545,631,000	6,685,500,000	7,436,430,000
Total assets	11,247,902,000	11,264,700,000	11,551,910,000
Corporate, other and eliminations
Financial information relating to segments
Net sales	(18,900,000)	(24,400,000)
Cost of sales (exclusive of depreciation, amortization and depletion)	(12,300,000)	4,900,000
Selling, general and administrative	1,200,000	900,000
Depreciation, amortization and depletion	2,200,000	800,000
Exploration	4,500,000	6,800,000
Operating income	(14,500,000)	(37,800,000)
Capital investment	1,300,000	2,400,000
Property, net	94,300,000	85,800,000
Total assets	(859,600,000)	658,300,000
Mexican Open-Pit | Operating segment
Financial information relating to segments
Net sales	664,200,000	648,200,000
Cost of sales (exclusive of depreciation, amortization and depletion)	299,200,000	229,500,000
Selling, general and administrative	9,400,000	8,700,000
Depreciation, amortization and depletion	54,100,000	54,700,000
Exploration	800,000	900,000
Environmental reclamation	5,900,000
Operating income	294,800,000	354,400,000
Capital investment	184,700,000	267,700,000
Property, net	4,502,600,000	3,764,700,000
Total assets	7,569,800,000	6,314,900,000
Mexican IMMSA Unit | Operating segment
Financial information relating to segments
Net sales	90,300,000	95,900,000
Cost of sales (exclusive of depreciation, amortization and depletion)	89,900,000	84,400,000
Selling, general and administrative	4,000,000	3,700,000
Depreciation, amortization and depletion	7,700,000	7,800,000
Exploration	2,300,000	5,000,000
Operating income	5,300,000	19,400,000
Capital investment	6,600,000	9,000,000
Property, net	388,300,000	380,800,000
Total assets	890,600,000	863,000,000
Mexican IMMSA Unit | Intersegment sales
Financial information relating to segments
Net sales	18,900,000	24,400,000
Peruvian Operations | Operating segment
Financial information relating to segments
Net sales	520,300,000	610,300,000
Cost of sales (exclusive of depreciation, amortization and depletion)	303,000,000	323,100,000
Selling, general and administrative	10,300,000	11,200,000
Depreciation, amortization and depletion	53,000,000	47,200,000
Exploration	2,700,000	1,900,000
Operating income	151,300,000	226,900,000
Capital investment	53,200,000	57,800,000
Property, net	2,560,400,000	2,454,200,000
Total assets	$ 3,647,100,000	$ 3,428,500,000