Quarterly report pursuant to Section 13 or 15(d)

Significant Accounting Policies (Schedule Of Rental Property Improvements) (Details)

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Significant Accounting Policies (Schedule Of Rental Property Improvements) (Details) - USD ($)
$ in Thousands
6 Months Ended 12 Months Ended
Jun. 30, 2018
Dec. 31, 2017
Property, Plant and Equipment [Line Items]    
Land held for development (including pre-development costs, if any) $ 498,701 $ 483,432
Development and construction in progress, including land 506,117 535,971
Total 1,004,818 1,019,403
Buildings and improvement 204,000 188,100
Development [Member]    
Property, Plant and Equipment [Line Items]    
Land $ 71,700 $ 77,000