Commitments and Contingencies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($)	Sep. 30, 2025 USD ($)	Oct. 16, 2023 USD ($)	Sep. 30, 2023 USD ($)	Oct. 16, 2021 USD ($)	Jan. 01, 2017 USD ($)
Loss Contingencies [Line Items]
Reserves for warranties and general liability	$ 7.7	$ 7.2
Payments from reserves	1.8	$ 1.4
Letters of credit outstanding, amount	$ 13.0
Operating partnership units, outstanding | shares	934,405
Operating partnership units outstanding, fair value	$ 136.5
Congressional Plaza | Put Option
Loss Contingencies [Line Items]
Maximum partnership percentage required to purchase	100.00%
Indexed ownership interest percentage	29.47%
Congressional Plaza | Put Option | Minimum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 78.0
Congressional Plaza | Put Option | Maximum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 82.0
Project In Southern California | Put Option
Loss Contingencies [Line Items]
Indexed ownership interest percentage	10.00%
Montrose Crossing | Minimum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 8.0
Montrose Crossing | Maximum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 9.0
Montrose Crossing | Put Option
Loss Contingencies [Line Items]
Indexed ownership interest percentage	10.10%
Plaza El Segundo | Minimum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 21.0
Plaza El Segundo | Maximum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 24.0
Plaza El Segundo | Put Option
Loss Contingencies [Line Items]
Number of members with purchase options	2
Grove at Shrewsbury and Brook 35 | Minimum
Loss Contingencies [Line Items]
Estimated maximum liability upon exercise of the put option	$ 9.0
Grove at Shrewsbury and Brook 35 | 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 | Plaza El Segundo | Maximum
Loss Contingencies [Line Items]
Purchase price under option							$ 4.9
Scenario, Forecast | The Grove at Shrewsbury | Put Option
Loss Contingencies [Line Items]
Indexed ownership interest percentage							4.80%
Scenario, Forecast | Brook 35 | Put Option
Loss Contingencies [Line Items]
Indexed ownership interest percentage							8.80%
Scenario, Forecast | Melville Mall
Loss Contingencies [Line Items]
Purchase price under option				$ 5.0		$ 5.0
Capital improvement, development, and redevelopment projects
Loss Contingencies [Line Items]
Contractual obligations	$ 381.1
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%