Derivative Financial Instruments (Schedule of Derivative Financial Instruments) (Details) In Thousands, unless otherwise specified	Dec. 31, 2012 USD ($)	Dec. 31, 2012 ZAR	Dec. 31, 2012 South African Facility [Member] ZAR	Dec. 31, 2012 Colombian Long-Term Credit Facility [Member] COP
Notional Amount	$ 107,256	423,634		101,250,000
Carrying Amount and Fair Value	$ (5,442)		(20,441)	(5,356,377)