Fair Value Measurements Input Hierarchy of Items Measured at Fair Value on a Non-Recurring Basis (Details) (Fair Value, Measurements, Nonrecurring [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Mar. 31, 2011
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Brazil Intrastate tax credits	$ 0	$ 0
Property Received in non-monetary exchange	26,845	0
Total Assets	26,845	0
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Brazil Intrastate tax credits	37,711	53,594
Property Received in non-monetary exchange	0	0
Total Assets	37,711	53,594
Total Assets / Liabilities, at Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Brazil Intrastate tax credits	37,711	53,594
Property Received in non-monetary exchange	26,845	0
Total Assets	$ 64,556	$ 53,594