Basis Of Presentation And Summary Of Significant Accounting Policies (Schedule Of Financial Instruments Having Difference Between Carrying Amount And Fair Value) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Basis Of Presentation And Summary Of Significant Accounting Policies [Abstract]
Investment in direct financing lease, Carrying Amount	$ 10,424	$ 10,798
Investment in direct financing lease, Fair Value	12,361	12,613
Note receivable from APM, Carrying Amount	4,914	4,749
Note receivable from APM, Fair Value	8,654	7,825
Debt, Carrying Amount	(1,180,386)	(1,245,014)
Debt, Fair Value	$ (1,234,138)	$ (1,302,550)