Real Estate - Portfolio (Summary Of Real Estate Subject To Operating Leases) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Property Subject to or Available for Operating Lease [Line Items]
Real estate dubject to operating leases, gross	$ 4,075,495	$ 4,033,718
Less accumulated depreciation and amortization	(350,868)	(332,172)
Real estate subject to operating leases before work in process	3,724,627	3,701,546
Real estate subject to operating leases, net	3,801,517	3,788,053
Land And Improvements [Member]
Property Subject to or Available for Operating Lease [Line Items]
Real estate subject to operating leases, gross	1,479,280	1,470,348
Buildings And Improvements [Member]
Property Subject to or Available for Operating Lease [Line Items]
Buildings and improvements	2,594,925	2,562,080
Leasehold Interests [Member]
Property Subject to or Available for Operating Lease [Line Items]
Leasehold interests	1,290	1,290
Work In Progress [Member]
Property Subject to or Available for Operating Lease [Line Items]
Work in progess	$ 76,890	$ 86,507