Fair Value Measurements (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Using Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis
Available-for-sale real estate equity securities	$ 208,219	$ 151,062
Real estate related bonds	0	0
Total assets	208,219	151,062
Derivative interest rate instruments	0	0
Total liabilities	0	0
Using Significant Other Observable Inputs (Level 2) [Member]
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis
Available-for-sale real estate equity securities	0	0
Real estate related bonds	3,648	3,691
Total assets	3,648	3,691
Derivative interest rate instruments	(1,669)	(1,744)
Total liabilities	(1,669)	(1,744)
Using Significant Other Unobservable Inputs (Level 3) [Member]
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis
Available-for-sale real estate equity securities	0	0
Real estate related bonds	0	0
Total assets	0	0
Derivative interest rate instruments	0	0
Total liabilities	0	0
Interest Rate Swap [Member] | Using Significant Other Observable Inputs (Level 2) [Member]
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis
Derivative, Notional Amount	$ 47,000	$ 51,283