Significant Transactions During the Nine Months Ended September 30, 2023 and Subsequent Events (Details) $ / shares in Units, $ in Millions	1 Months Ended						9 Months Ended
	Sep. 30, 2023 USD ($)	Jul. 31, 2023 USD ($) property	Jun. 30, 2023 USD ($)	May 31, 2023 USD ($)	Apr. 30, 2023 USD ($) apartment	Mar. 31, 2023 USD ($) apartment	Sep. 30, 2023 USD ($) $ / shares shares
Other Commitments [Line Items]
Treasury stock acquired, average cost per share (in dollars per share) | $ / shares							$ 218.88
Number of properties | property		4
Secured Debt
Other Commitments [Line Items]
Secured loans		$ 298.0
Fixed interest rate term		10 years
Interest rate		5.08%
Unsecured debt
Other Commitments [Line Items]
Secured loans	$ 300.0						$ 300.0
Repayments of unsecured debt				$ 300.0
Stock Repurchase Plan
Other Commitments [Line Items]
Shares repurchased and retired during period (in shares) | shares							437,026
Shares repurchased and retired during period, value							$ 95.7
Purchase authority remaining under stock repurchase plan	302.7						302.7
Stock repurchase plan amount	500.0						$ 500.0
Multifamily Community Located In Southern California
Other Commitments [Line Items]
Proceeds from dispositions of co-investments	$ 12.3
Preferred return rate	13.50%
Preferred Equity Investment Property in Southern California
Other Commitments [Line Items]
Proceeds from dispositions of co-investments			$ 14.7
Early redemption fee			$ 0.3
Preferred Equity Investment Property In Northern California
Other Commitments [Line Items]
Proceeds from dispositions of co-investments					$ 11.2
Hacienda at Camarillo Oaks
Other Commitments [Line Items]
Number of units acquired | apartment					73
Payments to acquire real estate					$ 23.1
CBC and The Sweeps
Other Commitments [Line Items]
Number of units acquired | apartment						239
Payments to acquire real estate						$ 91.7
Gain on sale of properties						$ 54.5