Fair Value - Classification Between the Three Levels of the Fair Value Hierarchy (Details) - Recurring basis - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Estimate of Fair Value Measurement
Financial Instruments Measured/Discussed at Fair Value
DownREIT units	$ (1,382)	$ (1,895)
Total	(6,907,086)	(8,563,805)
Fixed rate unsecured notes | Estimate of Fair Value Measurement
Financial Instruments Measured/Discussed at Fair Value
Indebtedness	(6,280,228)	(7,624,560)
Mortgage notes payable and variable rate unsecured notes | Estimate of Fair Value Measurement
Financial Instruments Measured/Discussed at Fair Value
Indebtedness	(655,522)	(940,779)
Interest Rate Caps | Not Designated as Hedging Instrument | Estimate of Fair Value Measurement
Financial Instruments Measured/Discussed at Fair Value
Derivative assets	722	225
Interest Rate Swaps | Cash Flow Hedges | Estimate of Fair Value Measurement
Financial Instruments Measured/Discussed at Fair Value
Derivative assets	29,324	3,204
Quoted Prices in Active Markets for Identical Asset (Level 1)
Financial Instruments Measured/Discussed at Fair Value
DownREIT units	(1,382)	(1,895)
Total	(6,281,610)	(7,626,455)
Quoted Prices in Active Markets for Identical Asset (Level 1) | Fixed rate unsecured notes
Financial Instruments Measured/Discussed at Fair Value
Indebtedness	(6,280,228)	(7,624,560)
Significant Other Observable Inputs (Level 2)
Financial Instruments Measured/Discussed at Fair Value
Total	(625,476)	(937,350)
Significant Other Observable Inputs (Level 2) | Mortgage notes payable and variable rate unsecured notes
Financial Instruments Measured/Discussed at Fair Value
Indebtedness	(655,522)	(940,779)
Significant Other Observable Inputs (Level 2) | Interest Rate Caps | Not Designated as Hedging Instrument
Financial Instruments Measured/Discussed at Fair Value
Derivative assets	722	225
Significant Other Observable Inputs (Level 2) | Interest Rate Swaps | Cash Flow Hedges
Financial Instruments Measured/Discussed at Fair Value
Derivative assets	29,324	3,204
Significant Unobservable Inputs (Level 3)
Financial Instruments Measured/Discussed at Fair Value
Total	$ 0	$ 0