SIGNIFICANT ACCOUNTING POLICIES (UNITED DOMINION REALTY, L.P.) (Details) $ in Millions	3 Months Ended
Jun. 30, 2020 USD ($)
Accounting policies
Adjustment to rental income	$ 8.5
Adjustment to income (loss)	0.5
Multifamily tenant lease
Accounting policies
Allowance for doubtful accounts	5.5
Retail tenant lease
Accounting policies
Allowance for doubtful accounts	3.5
Straight-line lease
Accounting policies
Allowance for doubtful accounts	2.9
United Dominion Realty L.P.
Accounting policies
Unrecognized Tax Benefits	0.0
Adjustment to rental income	4.6
United Dominion Realty L.P. \| Multifamily tenant lease
Accounting policies
Allowance for doubtful accounts	2.0
United Dominion Realty L.P. \| Retail tenant lease
Accounting policies
Adjustment to rental income	2.6
United Dominion Realty L.P. \| Straight-line lease
Accounting policies
Adjustment to income (loss)	$ 2.2

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=118939070&loc=d3e15032-111544

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L.1)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

Name:	us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant