Commitments and Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2025	Oct. 16, 2023	Sep. 30, 2023	Oct. 16, 2021
Loss Contingencies [Line Items]
Reserves for warranties and general liability	$ 3.0	$ 3.1
Payments from reserves	1.3	$ 1.4
Letters of credit outstanding, amount	$ 4.3
DownREIT operating partnership units, outstanding	609,584
Operating partnership units outstanding, fair value	$ 78.5
Congressional Plaza | Put Option
Loss Contingencies [Line Items]
Indexed ownership interest percentage	26.63%
Maximum partnership percentage required to purchase	100.00%
Congressional Plaza | Put Option | Minimum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 79.0
Congressional Plaza | Put Option | Maximum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 84.0
Plaza El Segundo | Put Option
Loss Contingencies [Line Items]
Number of members with purchase options	2
Plaza El Segundo | Put Option | Minimum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 30.0
Plaza El Segundo | Put Option | Maximum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 33.0
The Grove at Shrewsbury | Put Option
Loss Contingencies [Line Items]
Indexed ownership interest percentage	4.10%
Brook 35 | Put Option
Loss Contingencies [Line Items]
Indexed ownership interest percentage	6.50%
Grove at Shrewsbury and Brook 35 | Put Option | Minimum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 7.0
Grove at Shrewsbury and Brook 35 | Put Option | Maximum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 8.0
Hoboken | Put Option
Loss Contingencies [Line Items]
Indexed ownership interest percentage	10.00%
Hoboken | Put Option | Minimum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 9.0
Hoboken | Put Option | Maximum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 10.0
Scenario, Forecast | Mercer Mall
Loss Contingencies [Line Items]
Purchase price under option					$ 55.0
Scenario, Forecast | Mercer Mall | Put Option
Loss Contingencies [Line Items]
Purchase price under option			$ 60.0
Scenario, Forecast | Melville Mall
Loss Contingencies [Line Items]
Purchase price under option						$ 5.0
Scenario, Forecast | Melville Mall | Put Option
Loss Contingencies [Line Items]
Purchase price under option				$ 5.0
Member One In Plaza El Segundo | Plaza El Segundo | Put Option
Loss Contingencies [Line Items]
Indexed ownership interest percentage	10.00%
Member Two In Plaza El Segundo | Plaza El Segundo | Put Option
Loss Contingencies [Line Items]
Indexed ownership interest percentage	11.80%
Capital Improvement, Development, and Redevelopment Projects
Loss Contingencies [Line Items]
Contractual obligations	$ 572.4