COVID-19 Pandemic (Narrative) (Details) - COVID-19 - employee	3 Months Ended
	Jun. 30, 2021	Jul. 31, 2021
Unusual or Infrequent Item, or Both [Line Items]
Rent collected, percent	97.00%
Office
Unusual or Infrequent Item, or Both [Line Items]
Rent collected, percent	98.00%
Retail
Unusual or Infrequent Item, or Both [Line Items]
Rent collected, percent	93.00%
Building Maintenance Service LLC | Subsequent Event
Unusual or Infrequent Item, or Both [Line Items]
Percentage of employees returned from furlough		72.00%
Number of employees furloughed		1,293