Significant Transactions During the Nine Months Ended September 30, 2026 and Subsequent Events - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended					3 Months Ended		9 Months Ended
	Oct. 28, 2026 USD ($) apartment	Sep. 30, 2026 USD ($) extensionOption investment community $ / shares	Feb. 28, 2026 USD ($)	Aug. 31, 2025 USD ($)	Aug. 31, 2022 USD ($)	Sep. 30, 2026 USD ($) investment community $ / shares	Jun. 30, 2026 USD ($)	Sep. 30, 2026 USD ($) investment community $ / shares shares	Sep. 30, 2025 USD ($)	May 31, 2026 USD ($)
Other Commitments [Line Items]
Apartment communities owned (in communities) | community		255				255		255
Debt instrument face amount		$ 600,000				$ 600,000		$ 600,000
Net proceeds (costs) from issuance of common units								$ 16,215	$ (280)
Common stock repurchased and retired (in shares) | shares								254,001
Repurchase of common stock								$ 61,915	0
Shares repurchased, Average price per share (in dollar per share) | $ / shares								$ 243.76
Payments to acquire real estate								$ 6,142	$ 686,681
Unsecured Term Loan 0.800%, Due September 2029 | Unsecured Debt
Other Commitments [Line Items]
Debt instrument face amount		$ 275,000				$ 275,000		$ 275,000
Interest rate (in percent)		0.80%				0.80%		0.80%
Number of extension options (in extensions) | extensionOption		2
Extension period (in years)		1 year
Line of credit facility increase amount		$ 225,000
Option to increase		500,000				$ 500,000		$ 500,000
Stock Repurchase Plan
Other Commitments [Line Items]
Purchase authority remaining under stock repurchase plan		$ 500,000				$ 500,000		$ 500,000
Share repurchase program, authorized, amount										$ 500,000
Equity Forward Sale Agreements
Other Commitments [Line Items]
Number of shares issued (in shares) | shares								52,600
Sale of stock, price per share | $ / shares		$ 311.13				$ 311.13		$ 311.13
Net proceeds (costs) from issuance of common units								$ 16,400
Purchase authority remaining under stock repurchase plan		$ 883,500				$ 883,500		$ 883,500
Wesco VII LLC
Other Commitments [Line Items]
Joint venture ownership percent		50.00%				50.00%		50.00%
Preferred equity investment		$ 36,200				$ 36,200		$ 36,200
Apartment communities owned (in communities) | community		2				2		2
Preferred return rate (in percent)						11.50%
Number of investments with a commitment to fund | investment		3				3		3
Preferred Equity Investment Property In California
Other Commitments [Line Items]
Cash received, preferred equity investments						$ 15,600	$ 42,100
Early redemption fee						$ 200
Number of investments with a commitment to fund | investment		2				2		2
Apartment Home Community Built in 2024 and Located in Oakland, CA | Subsequent Event
Other Commitments [Line Items]
Apartment homes (in apartments) | apartment	378
Subordinated loan liquidation	$ 64,200
Debt instrument, repaid, principal	$ 92,300
Apartment Home Community Built in 2022 and Located in Hayward, CA | Subsequent Event
Other Commitments [Line Items]
Apartment homes (in apartments) | apartment	474
Payments to acquire real estate	$ 205,300
Related Party
Other Commitments [Line Items]
Notes receivable					$ 11,200
Notes receivable, interest rate (in percent)					9.50%
Notes Receivable, Mezzanine Loan Property In Northern California
Other Commitments [Line Items]
Cash received, financing receivable						$ 45,700
Related Party Bridge Loan On Property Acquired By Wesco I | Related Party
Other Commitments [Line Items]
Notes receivable			$ 59,500	$ 81,200
Notes receivable, interest rate (in percent)			5.00%	5.50%