Derivative Instruments And Hedging Activities Interest Rate Swaps (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Derivative Instruments And Hedging Activities [Abstract]
Other Comprehensive Income (Loss), Change in Fair Value of Cash Flow Hedge	$ (1,802)	$ (1,110)	$ (2,438)	$ (1,175)
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	(235)	271	685	1,554
Cash Flow Hedge Loss Reclassified to Interest Expense	1,567	1,381	3,123	2,729
Cash Flow Hedge Gain (Loss) Reclassified to Interest Expense, Net	$ (1,567)	$ (1,381)	$ (3,123)	$ (2,729)