Derivative Instruments And Hedging Activities (Fair Value Of Derivatives Designated As Hedging Instruments) (Details) (Variable Interest Rate Swaps [Member], Other Non-Current Assets [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Mar. 31, 2011
Variable Interest Rate Swaps [Member] | Other Non-Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of interest rate swaps	$ 7,037	$ 5,086