COVID-19 - Collections and Agreements with Tenants (Details) - USD ($)		1 Months Ended	3 Months Ended	9 Months Ended
	Nov. 04, 2020	Oct. 31, 2020	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019
Unusual or Infrequent Item, or Both [Line Items]
Bad debt expense				$ 2,311,000	$ 73,000
COVID-19 Pandemic
Unusual or Infrequent Item, or Both [Line Items]
Bad debt expense			$ 1,361,000	$ 1,856,000
COVID-19 Pandemic, Billings In Prior Quarters
Unusual or Infrequent Item, or Both [Line Items]
Bad debt expense			422,000
Office and Retail
Unusual or Infrequent Item, or Both [Line Items]
Rental and Other Property Income Billed to Tenants			$ 14,250,689
% Collected			95.50%
% Collected by Applying the Security Deposit			0.10%
% Deferred			0.20%
% Recorded as Bad Debt			1.50%
% Abated			0.00%
Office and Retail | Subsequent Event
Unusual or Infrequent Item, or Both [Line Items]
Rental and Other Property Income Billed to Tenants		$ 4,333,864
% Collected		92.80%
% Collected by Applying the Security Deposit		0.00%
% Deferred		0.00%
% Recorded as Bad Debt		0.00%
% Abated		0.00%
Office and Retail | Subsequent Event | Three Months Ended September 30, 2020
Unusual or Infrequent Item, or Both [Line Items]
Rental and other property income billed to tenants, additionally collected	1.40%
Office and Retail | Subsequent Event | October 2020
Unusual or Infrequent Item, or Both [Line Items]
Rental and other property income billed to tenants, additionally collected	0.20%
Parking
Unusual or Infrequent Item, or Both [Line Items]
Rental and Other Property Income Billed to Tenants			$ 1,157,579
% Collected			34.90%
% Collected by Applying the Security Deposit			0.00%
% Deferred			0.00%
% Recorded as Bad Debt			62.60%
% Abated			0.00%
Parking | Subsequent Event
Unusual or Infrequent Item, or Both [Line Items]
Rental and Other Property Income Billed to Tenants		$ 351,202
% Collected		19.20%
% Collected by Applying the Security Deposit		0.00%
% Deferred		0.00%
% Recorded as Bad Debt		0.00%
% Abated		0.00%