Real Estate Fund Investments - Schedule of Financial Information for Fund Investment (Details) - Unconsolidated Real Estate Funds [Member] - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Property Fund II [Member]
Investment Holdings [Line Items]
Real estate investments	$ 51	$ 64,989
Cash and cash equivalents	826	1,297
Other assets	115	127
Total assets	992	66,413
Other liabilities	45	60
Total liabilities	45	60
Equity	947	66,353
Total liabilities and equity	992	66,413
Property Fund III [Member]
Investment Holdings [Line Items]
Real estate investments	15,701	39,376
Cash and cash equivalents	2,305	2,221
Total assets	18,006	41,597
Other liabilities	29	49
Total liabilities	29	49
Equity	17,977	41,548
Total liabilities and equity	18,006	41,597
Property Fund VII [Member]
Investment Holdings [Line Items]
Real estate investments	33,259	165,556
Cash and cash equivalents	762	741
Other assets	2
Total assets	34,023	166,297
Other liabilities	618	1,483
Total liabilities	618	1,483
Equity	33,405	164,814
Total liabilities and equity	$ 34,023	$ 166,297