Real Estate - Portfolio (Summary Of Real Estate Subject To Operating Leases) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Property Subject to or Available for Operating Lease [Line Items]
Real Estate Subject to Operating Leases, Gross	$ 3,608,057	$ 3,432,885
Less accumulated depreciation and amortization	(285,560)	(269,687)
Real estate subject to operating leases before work in process	3,322,497	3,163,198
Real estate subject to operating leases, net	3,393,906	3,223,304
Land And Improvements [Member]
Property Subject to or Available for Operating Lease [Line Items]
Real estate subject to operating leases, gross	1,368,270	1,314,438
Buildings And Improvements [Member]
Property Subject to or Available for Operating Lease [Line Items]
Buildings and improvements	2,238,497	2,117,157
Leasehold Interests [Member]
Property Subject to or Available for Operating Lease [Line Items]
Leasehold interests	1,290	1,290
Work In Process [Member]
Property Subject to or Available for Operating Lease [Line Items]
Work in process	$ 71,409	$ 60,106