Real Estate - Portfolio (Summary Of Real Estate Subject To Operating Leases) (Details) (USD $)	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Property Subject to or Available for Operating Lease [Line Items]
Deferred Revenue, Leases, Allowances	$ 4,870,000	$ 3,609,000
Deferred Revenue, Leases, Net	25,187,000	25,535,000
Deferred Revenue, Revenue Recognized	(222,000)	(93,000)	2,102,000
Real estate subject to operating leases, gross	3,434,103,000	2,710,318,000
Less accumulated depreciation and amortization	270,094,000	222,406,000
Real estate subject to operating leases before work in process	3,164,009,000	2,487,912,000
Work in process	60,322,000	26,699,000	5,634,000
Operating Leases, Future Minimum Payments Receivable, Current	280,328,000
Real estate subject to operating leases, net	3,224,023,000	2,514,302,000
Operating Leases, Future Minimum Payments Receivable, in Two Years	273,762,000
Operating Leases, Future Minimum Payments Receivable, in Three Years	264,869,000
Operating Leases, Future Minimum Payments Receivable, in Four Years	257,821,000
Operating Leases, Future Minimum Payments Receivable, in Five Years	251,055,000
Operating Leases, Future Minimum Payments Receivable, Thereafter	2,151,781,000
Operating Leases, Future Minimum Payments Receivable	3,479,616,000
Land And Improvements [Member]
Property Subject to or Available for Operating Lease [Line Items]
Real estate subject to operating leases, gross	1,314,157,000	1,117,915,000
Buildings And Improvements [Member]
Property Subject to or Available for Operating Lease [Line Items]
Buildings and improvements	2,118,656,000	1,591,113,000
Leasehold Interests [Member]
Property Subject to or Available for Operating Lease [Line Items]
Leasehold interests	1,290,000	1,290,000
Work In Process [Member]
Property Subject to or Available for Operating Lease [Line Items]
Work in process	$ 60,014,000	$ 26,390,000