Derivative Financial Instruments (Narrative) (Details) In Millions, unless otherwise specified		3 Months Ended
	Mar. 31, 2013 USD ($)	Mar. 31, 2013 South African Facility [Member] USD ($) integer	Mar. 31, 2013 South African Facility [Member] ZAR	Mar. 31, 2013 Colombian Long Term Credit Facility [Member] USD ($) integer	Mar. 31, 2013 Colombian Long Term Credit Facility [Member] COP
Derivative [Line Items]
Notional Amount of Cash Flow Hedge Instruments		$ 45.9	423.6	$ 55.3	101,300.0
Derivative, Lower Fixed Interest Rate Range		6.09%	6.09%
Derivative, Higher Fixed Interest Rate Range		7.25%	7.25%
Derivative, Maturity Date		Mar. 31, 2020	Mar. 31, 2020	Nov. 30, 2020	Nov. 30, 2020
Number of interest rate swap agreements		9	9	1	1
Derivative, Fixed Interest Rate				5.78%	5.78%
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	$ 1.6