Forward and Swap Contracts Level 4 (Details) (USD $)					3 Months Ended
	Jun. 30, 2012 Other Assets [Member]	Mar. 31, 2012 Other Assets [Member]	Jun. 30, 2012 Accrued Liabilities [Member]	Mar. 31, 2012 Accrued Liabilities [Member]	Jun. 30, 2012 Selling, General and Administrative Expenses [Member]	Jun. 30, 2011 Selling, General and Administrative Expenses [Member]	Jun. 30, 2012 Cost of Sales [Member]	Jun. 30, 2011 Cost of Sales [Member]	Jun. 30, 2012 Mexico, Pesos	Jun. 30, 2012 Canada, Dollars	Jun. 30, 2012 212234 Copper Ore and Nickel Ore Mining [Member]
Derivative [Line Items]
Foreign Currency Transaction Gain, before Tax					$ (317,000)	$ 266,000
Notional Amount of Foreign Currency Derivative Purchase Contracts									106,300,000	2,300,000	391,000
Derivative Assets	103,000	12,000	0	0
Derivative Liabilities	0	0	791,000	863,000
Gain (Loss) on Sale of Commodity Contracts							$ (220,000)	$ (479,000)