Commitments and Contingencies (Details) (USD $)	6 Months Ended
	Jun. 30, 2012
Unfunded Commitments
Properties pledged as collateral book value	$ 3,790,000,000
Percentage of capital committed to strategic investments that may be drawn down	100.00%
Performance-Based Commitments	61,297,000
Discretionary Fundings	127,948,000
Other	25,090,000
Total	214,335,000
Unencumbered assets excluding cash and other assets carrying v	2,400,000,000
Loans
Unfunded Commitments
Performance-Based Commitments	44,038,000
Discretionary Fundings	127,948,000
Other	0
Total	171,986,000
Net Lease Assets
Unfunded Commitments
Performance-Based Commitments	17,259,000
Discretionary Fundings	0
Other	0
Total	17,259,000
Strategic Investments
Unfunded Commitments
Performance-Based Commitments	0
Discretionary Fundings	0
Other	25,090,000
Total	25,090,000
Unsecured debt
Unfunded Commitments
Debt maturities	$ 501,700,000