Commitments and Contingencies (Details) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021 USD ($) condominium_tower	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) condominium_tower	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Jun. 14, 2018 individualOrEntitie
Loss Contingencies [Line Items]
Number of individuals or entities on petition | individualOrEntitie						500
Loss contingency accrual for estimated repair costs					$ 5.7
Outstanding letters of credit	$ 5.1		$ 5.1		5.2
Amount of outstanding surety bonds	357.3		357.3		272.4
Contractual rent expense	$ 1.9	$ 2.0	$ 5.5	$ 5.3
Guarantor obligations, reserved percentage of residential units			20.00%
Guarantor obligations, number of open condominium towers | condominium_tower	3		3
Guarantor obligations, number of towers under construction | condominium_tower	3		3
Waiea
Loss Contingencies [Line Items]
Charge for repairs and remediation on alleged construction defects			$ 21.0		$ 99.2
Loss contingency accrual for estimated repair costs	$ 101.9		$ 101.9