SEGMENT AND RELATED INFORMATION: (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Provisionally priced sales
Provisional price sales adjustment amounts included in net sales	$ 1.6	$ 6.6
Copper
Provisionally priced sales
Provisional price sales adjustment amounts included in accounts receivable	1.0	2.9
Copper | January through February 2014
Provisionally priced sales
Nonmonetary notional amount of commodity (in million lbs.)	16,100,000
Provisional price	3.344
Molybdenum
Provisionally priced sales
Provisional price sales adjustment amounts included in accounts receivable	$ 0.6	$ 3.7
Molybdenum | January 2014 through April 2014
Provisionally priced sales
Nonmonetary notional amount of commodity (in million lbs.)	10,300,000
Provisional price	9.70