Summary Of Significant Accounting Policies Recently Adopted Accounting Pronouncements (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) property	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) property	Sep. 30, 2018 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of properties subject to ground leases | property	14		14
Cumulative impact to accumulated dividends in excess of net income			$ (7,098)	$ (6,028)
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized initial direct costs of leases excluding external leasing commissions	$ 700	$ 1,700	1,700	5,300
Accumulated Dividends in Excess of Net Income
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative impact to accumulated dividends in excess of net income			(7,098)	$ (6,028)
Accumulated Dividends in Excess of Net Income | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative impact to accumulated dividends in excess of net income			$ (7,100)