Derivative And Hedging Instruments (Schedule Of Effect Of Derivative Instruments Not Designated As Hedging Instruments In Consolidated Statements Of Income) (Details) (Interest Expense [Member], Interest Rate Caps [Member], Not Designated as Hedging Instrument [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Interest Expense [Member] | Interest Rate Caps [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) / Gain Recognized in Income on Derivatives	$ (7)	$ (61)	$ (66)	$ (202)