Investments in Joint Ventures Investments in Joint Ventures (Table Details) $ in Thousands		6 Months Ended		12 Months Ended
		Jun. 30, 2016 USD ($) properties		Dec. 31, 2015 USD ($) properties
Schedule of Equity Method and Cost Method Investments [Line Items]
Investments in Joint Ventures		$ 63,334		$ 64,158
Advances to unconsolidated joint ventures		381		442
Investments in and advances to unconsolidated joint ventures		$ 63,715		$ 64,600
G&I Investment South Florida Portfolio, LLC [Member] | FLORIDA
Schedule of Equity Method and Cost Method Investments [Line Items]
Number of Real Estate Properties | properties	[1]	1		1
Equity Method Investment, Ownership Percentage		20.00%	[1]	20.00%
Equity Method Investments	[1]	$ 3,740		$ 3,719
Madison 2260, Realty, LLC [Member] | NEW YORK
Schedule of Equity Method and Cost Method Investments [Line Items]
Number of Real Estate Properties | properties	[1]	1		1
Cost Method Investment, Ownership Percentage		8.60%	[1]	8.60%
Cost Method Investments	[1]	$ 526		$ 526
Madison 1235, Realty, LLC [Member] | NEW YORK
Schedule of Equity Method and Cost Method Investments [Line Items]
Number of Real Estate Properties | properties	[1]	1		1
Cost Method Investment, Ownership Percentage		20.10%	[1]	20.10%
Cost Method Investments	[1]	$ 820		$ 820
Parnassus Heights Medical Center [Member] | CALIFORNIA
Schedule of Equity Method and Cost Method Investments [Line Items]
Number of Real Estate Properties | properties	[1]	1		1
Equity Method Investment, Ownership Percentage		50.00%	[1]	50.00%
Equity Method Investments	[1]	$ 19,234		$ 19,263
Equity One JV Portfolio, LLC (NYCRF) [Member]
Schedule of Equity Method and Cost Method Investments [Line Items]
Equity Method Investment, Deferred Gain on Sale		$ 376		$ 376
Equity One JV Portfolio, LLC (NYCRF) [Member] | Florida, Massachusetts, New Jersey [Member]
Schedule of Equity Method and Cost Method Investments [Line Items]
Number of Real Estate Properties | properties	[1],[2]	6		6
Equity Method Investment, Ownership Percentage		30.00%	[1],[2]	30.00%
Equity Method Investments	[1],[2]	$ 38,383		$ 39,501
Other Equity Investment [Member]
Schedule of Equity Method and Cost Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1],[2]	45.00%
Equity Method Investments	[1],[3]	$ 631		$ 329

[1] All unconsolidated joint ventures are accounted for under the equity method except for the Madison 2260 Realty LLC and Madison 1235 Realty LLC joint ventures, which are accounted for under the cost method

[2] The investment balance as of June 30, 2016 and December 31, 2015 is presented net of a deferred gain of approximately $376,000 associated with the disposition of assets by us to the joint venture.

[3] In February 2015, we entered into a joint venture to explore a potential development opportunity in the Northeast. As of June 30, 2016 and December 31, 2015, the carrying amount of our investment reflects our maximum exposure to loss related to our investment in the joint venture.