Summary Of Significant Accounting Policies (Redeemable Noncontrolling Interests) (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 12, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Rollforward of Redeemable Noncontrolling Interests
Beginning balance		$ 141,157	$ 143,694
Net income		3,865	3,874	$ 2,713
Contributions		354	11,109
Distributions & Redemptions		(4,071)	(6,914)
Change in redemption value		(5,097)	(10,606)
Ending balance		$ 136,208	$ 141,157	$ 143,694
San Antonio Center
Redeemable Noncontrolling Interest [Line Items]
Payments to Acquire Outstanding Interest	$ 2,600
Number of downREIT units issued in connection with purchase option	44,195