Summary of Significant Accounting Policies (Segment Information to Taxes) (Details)	6 Months Ended
	Jun. 30, 2020 segment customer subsidiary	Jun. 30, 2019
Summary Of Significant Accounting Policies [Line Items]
Number of operating segments | segment	1
Number of reportable segments | segment	1
Number of subsidiaries taxed as taxable REIT subsidiaries. | subsidiary	2
Number of taxable REIT subsidiaries in a net deferred tax liability position | subsidiary	1
Customer One | Rental Revenue
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	10.60%
Number of customers | customer	1
Three Customers [Member] | Accounts Receivable | Trade Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	25.00%
Three Customers [Member] | Accounts Receivable | Minimum | Trade Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	5.00%
None Of These Customers [Member] | Accounts Receivable | Minimum | Trade Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	10.00%
Taxable REIT Subsidiaries
Summary Of Significant Accounting Policies [Line Items]
Effective tax rate	1.20%	(6.60%)