Schedule III - Consolidated Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances	[1]	$ 123,333
SEC Schedule III, Real Estate and Accumulated Depreciation, Initial Cost of Land		30,391
Real Estate Under Development		18,182
SEC Schedule III, Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	[2]	45,884
SEC Schedule III, Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs		122,215
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount of Land		30,391
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount Of Real Estate Under Development		137,666
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount of Buildings and Improvements	[2]	48,615
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Total		216,672	$ 78,658	$ 62,527
SEC Schedule III, Real Estate Accumulated Depreciation		3,608	$ 2,389	$ 2,143
Greenwich Ny 77 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances	[1]	47,719
SEC Schedule III, Real Estate and Accumulated Depreciation, Initial Cost of Land		0
Real Estate Under Development		16,634
SEC Schedule III, Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	[2]	0
SEC Schedule III, Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs		114,737
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount of Land		0
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount Of Real Estate Under Development		131,371
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount of Buildings and Improvements	[2]	0
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Total		131,371
SEC Schedule III, Real Estate Accumulated Depreciation		$ 0
SEC Schedule III, Real Estate And Accumulated Depreciation Date of Acquisition 1		1990
Paramus Nj [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances	[1]	$ 0
SEC Schedule III, Real Estate and Accumulated Depreciation, Initial Cost of Land		0
Real Estate Under Development		1,548
SEC Schedule III, Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	[2]	0
SEC Schedule III, Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs		4,747
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount of Land		0
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount Of Real Estate Under Development		6,295
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount of Buildings and Improvements	[2]	0
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Total		6,295
SEC Schedule III, Real Estate Accumulated Depreciation		$ 0
SEC Schedule III, Real Estate And Accumulated Depreciation Date of Acquisition 1		1980
SEC Schedule III, Real Estate And Accumulated Depreciation Date of Construction 1		1984
West Palm Beach, FL [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances	[1]	$ 9,046
SEC Schedule III, Real Estate and Accumulated Depreciation, Initial Cost of Land		2,452
Real Estate Under Development		0
SEC Schedule III, Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	[2]	3,707
SEC Schedule III, Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs		2,731
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount of Land		2,452
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount Of Real Estate Under Development		0
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount of Buildings and Improvements	[2]	6,438
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Total		8,890
SEC Schedule III, Real Estate Accumulated Depreciation		$ 2,640
SEC Schedule III, Real Estate And Accumulated Depreciation Date of Acquisition 1		2001
Brooklyn New York [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances	[1]	$ 66,568
SEC Schedule III, Real Estate and Accumulated Depreciation, Initial Cost of Land		27,939
Real Estate Under Development		0
SEC Schedule III, Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	[2]	42,177
SEC Schedule III, Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs		0
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount of Land		27,939
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount Of Real Estate Under Development		0
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount of Buildings and Improvements	[2]	42,177
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Total		70,116
SEC Schedule III, Real Estate Accumulated Depreciation		$ 968
SEC Schedule III, Real Estate And Accumulated Depreciation Date of Acquisition 1		2018
SEC Schedule III, Real Estate And Accumulated Depreciation Date of Construction 1		2017

[1] Encumbrances are net of deferred finance costs of approximately $5.1 million.

[2] Depreciation on buildings and improvements reflected in the consolidated statements of operations and comprehensive loss is calculated on the straight-line basis over estimated useful lives of 10 to 39 years.