Derivative Financial Instruments (Notional Amounts, Weighted-Average Fixed Rates, And Terms Associated With The Company's Interest Rate Swaps) (Details) In Thousands, unless otherwise specified	Mar. 31, 2013 USD ($)	Mar. 31, 2013 Derivative Remaining Term Year One [Member] USD ($)		Mar. 31, 2013 Derivative Remaining Term Year One [Member] U.S. [Member] USD ($)	Mar. 31, 2013 Derivative Remaining Term Year One [Member] U.K. [Member] GBP (£)	Mar. 31, 2013 Derivative Remaining Term Year Two [Member] USD ($)		Mar. 31, 2013 Derivative Remaining Term Year Two [Member] U.S. [Member] USD ($)	Mar. 31, 2013 Derivative Remaining Term Year Three [Member] USD ($)		Mar. 31, 2013 Derivative Remaining Term Year Three [Member] U.S. [Member] USD ($)	Mar. 31, 2013 Derivative Remaining Term Year Four [Member] USD ($)		Mar. 31, 2013 Derivative Remaining Term Year Four [Member] U.S. [Member] USD ($)	Mar. 31, 2013 Derivative Remaining Term Year Five [Member] USD ($)		Mar. 31, 2013 Derivative Remaining Term Year Five [Member] U.S. [Member] USD ($)	Mar. 31, 2013 Derivative Remaining Term Year Six [Member] USD ($)		Mar. 31, 2013 Derivative Remaining Term Year Six [Member] U.S. [Member] USD ($)
Derivative [Line Items]
Notional Amounts		$ 1,037,973	[1]	$ 1,000,000	£ 25,000	$ 1,250,000	[1]	$ 1,250,000	$ 1,300,000	[1]	$ 1,300,000	$ 1,300,000	[1]	$ 1,300,000	$ 1,000,000	[1]	$ 1,000,000	$ 750,000	[1]	$ 750,000
Weighted Average Fixed Rate		2.69%				2.98%			2.84%			2.74%			2.53%			2.54%
Exchange Rate	1.52

[1] U.K. pound sterling amounts have been converted into U.S. dollars at approximately $1.52 to £1.00, which was the exchange rate in effect as of March 31, 2013.