Summary Of Significant Accounting Policies Recently Adopted Accounting Pronouncements (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) property	Mar. 31, 2018 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of properties subject to ground leases | property	14
Cumulative impact to accumulated dividends in excess of net income	$ (7,098)	$ (6,028)
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized leasing costs excluding external commissions	400	1,600
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 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative impact to accumulated dividends in excess of net income	$ (7,100)