Summary Of Significant Accounting Policies Revenue Recognition (Details)	Sep. 30, 2017 condominiums
Condominiums \| Assembly Row and Pike & Rose
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of condominium units under construction	221

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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