Subsequent Event (Notes)	12 Months Ended
Dec. 31, 2019
Subsequent Event [Line Items]
Subsequent Event	SUBSEQUENT EVENT On January 10, 2020, we acquired a 49,000 square foot shopping center in Fairfax, Virginia for $22.3 million. This acquisition was funded by 163,322 downREIT operating partnership units.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-URI http://asc.fasb.org/topic&trid=2122774

Name:	us-gaap_SubsequentEventsTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration