Revenues (Narrative) (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2021
Revenues [Abstract]
Reduction of net income due to recording of revenue on cash basis and write off outstanding straight-line receivable	$ 0	$ 100,000
Unpaid billed charges of rent and tenant reimbursements	500,000	900,000
Unrecorded revenue from tenants	$ 500,000	$ 900,000