Real Estate Fund Investments - Schedule of Financial Information for Fund Investment (Details) - Unconsolidated Real Estate Funds [Member] - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Property Fund II [Member]
Investment Holdings [Line Items]
Real estate investments	$ 11,151	$ 64,989
Cash and cash equivalents	882	1,297
Other assets	115	127
Total assets	12,148	66,413
Other liabilities	90	60
Total liabilities	90	60
Equity	12,058	66,353
Total liabilities and equity	12,148	66,413
Property Fund III [Member]
Investment Holdings [Line Items]
Real estate investments	19,669	39,376
Cash and cash equivalents	2,102	2,221
Total assets	21,771	41,597
Other liabilities	75	49
Total liabilities	75	49
Equity	21,696	41,548
Total liabilities and equity	21,771	41,597
Property Fund VII [Member]
Investment Holdings [Line Items]
Real estate investments	158,822	165,556
Cash and cash equivalents	2,676	741
Other assets	97
Total assets	161,595	166,297
Other liabilities	1,531	1,483
Total liabilities	1,531	1,483
Equity	160,064	164,814
Total liabilities and equity	$ 161,595	$ 166,297