Debt (Details 3) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Feb. 29, 2008
Revolving Loans
Revolving loans
Total Amount Committed by Lenders	$ 443.6
Outstanding Letters of Credit	131.9
Total Amount Available	311.7
U.S. Dollar revolving loans under the Amended Credit Agreement
Revolving loans
Total Amount Committed by Lenders	250.0	230.0
Outstanding Letters of Credit	0.3
Total Amount Available	249.7
Other revolving loans
Revolving loans
Total Amount Committed by Lenders	193.6
Outstanding Letters of Credit	131.6
Total Amount Available	$ 62.0