Schedule III - Consolidated Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances	$ 169,741
SEC Schedule III, Real Estate and Accumulated Depreciation, Initial Cost of Land	27,939
Real Estate Under Development	18,182
SEC Schedule III, Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	42,177
SEC Schedule III, Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	207,491
Real Estate And Accumulated Depreciation Buildings And Improvements	14
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	225,673
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount of Buildings and Improvements	42,191
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Total	295,803	$ 216,672	$ 78,658
SEC Schedule III, Real Estate Accumulated Depreciation	2,577	$ 3,608	$ 2,389
Deferred Offering Costs, Net	$ 2,600
Property, Plant and Equipment, Useful Life	1 year
Greenwich Ny 77 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances	$ 102,285
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	0
SEC Schedule III, Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	201,986
Real Estate And Accumulated Depreciation Buildings And Improvements	0
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	218,620
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount of Buildings and Improvements	0
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Total	218,620
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	$ 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	0
SEC Schedule III, Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	5,505
Real Estate And Accumulated Depreciation Buildings And Improvements	0
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	7,053
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Amount of Buildings and Improvements	0
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Total	7,053
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
Brooklyn New York [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances	$ 67,456
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	42,177
SEC Schedule III, Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate And Accumulated Depreciation Buildings And Improvements	14
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	42,191
SEC Schedule III, Real Estate and Accumulated Depreciation, Carried Total	70,130
SEC Schedule III, Real Estate Accumulated Depreciation	$ 2,577
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
Maximum [Member]
Property, Plant and Equipment, Useful Life	39 years
Minimum [Member]
Property, Plant and Equipment, Useful Life	10 years