Derivatives Financial Instruments (Schedule Of Interest Rate Swaps) (Details) (USD $) In Thousands	Jun. 30, 2011
Notional Amount	$ 310,000
Fair Value Gain (Loss)	(10,008)
Cash Flow [Member] | Total Interest Rate Caps [Member]
Notional Amount	60,000
Fair Value Gain (Loss)	547
Cash Flow [Member] | Total Interest Rate Swap [Member]
Notional Amount	250,000
Fair Value Gain (Loss)	(10,555)
Cash Flow [Member] | Interest Rate Swap 1 [Member]
Notional Amount	20,000
Fair Value Gain (Loss)	(252)
Cash Flow [Member] | Interest Rate Swap 2 [Member]
Notional Amount	40,000
Fair Value Gain (Loss)	(506)
Cash Flow [Member] | Interest Rate Swap 3 [Member]
Notional Amount	25,000
Fair Value Gain (Loss)	(230)
Cash Flow [Member] | Interest Rate Swap 4 [Member]
Notional Amount	50,000
Fair Value Gain (Loss)	(5,019)
Cash Flow [Member] | Interest Rate Swap 5 [Member]
Notional Amount	40,000
Fair Value Gain (Loss)	(4,072)
Cash Flow [Member] | Interest Rate Swap 6 [Member]
Notional Amount	50,000	[1]
Fair Value Gain (Loss)	(330)	[1]
Cash Flow [Member] | Interest Rate Swap 7 [Member]
Notional Amount	25,000	[1]
Fair Value Gain (Loss)	(146)	[1]
Interest Rate Caps 1 [Member]
Notional Amount	20,000	[1]
Fair Value Gain (Loss)	182	[1]
Interest Rate Caps 2 [Member]
Notional Amount	40,000	[1]
Fair Value Gain (Loss)	$ 365	[1]

[1] Forward starting in the third and fourth quarters of 2011