Organization and Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025 USD ($) Properties Property Community State shares	Jun. 30, 2024 USD ($) shares	Jun. 30, 2025 USD ($) Properties Property Community State shares	Jun. 30, 2024 USD ($) shares	Dec. 31, 2028 Property	Dec. 31, 2027 Property	Dec. 31, 2026 Property	Dec. 31, 2025 Property	Dec. 31, 2024 USD ($) shares
Real Estate Properties [Line Items]
General Partners' Capital Account, Units Outstanding | shares	117,071,410	116,858,044	117,071,410	116,858,044
Number of Real Estate Properties | Community	291		291
Number of units under development community | Properties	2,648		2,648
Development and capital improvements in progress	$ 484,955		$ 484,955						$ 470,282
Number of States in which Entity Operates | State	16		16
Consolidated assets	$ 11,835,597		$ 11,835,597						11,812,369
Consolidated liabilities	5,745,197		5,745,197						$ 5,664,705
Real Estate Investments, Joint Ventures	$ 23,200		$ 23,200
Percentage Of Rental Revenue From Leasing Of Apartment Homes			94.00%
Percentage Of Reimbursable Revenue From Leasing Of Apartment Homes			5.00%
Percentage of Rental Revenue and Other Income From Non-leasing Activities			1.00%
Operating Lease, Right-of-Use Asset, Statement of Financial Position	Other assets		Other assets						Other assets
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Accrued expenses and other liabilities		Accrued expenses and other liabilities
Operating Lease, Right-of-Use Asset	$ 39,300		$ 39,300						$ 40,500
Right-of-use Lease, Liability	25,238		25,238						26,100
Net proceeds from sale of marketable equity securities		$ 6,700	0	$ 6,729
Net realized / unrealized gain on sale		5,600
Marketable equity securities	1,900		1,900						3,300
Marketable Equity Securities [Member]
Real Estate Properties [Line Items]
Investment Expense	400	1,200	1,400	4,200
Limited Partnership [Member]
Real Estate Properties [Line Items]
Investment Income		$ 300	1,600	$ 8,500
Investment Expense	100
Other Assets [Member]
Real Estate Properties [Line Items]
Real Estate Investments, Joint Ventures	71,300		71,300						62,200
Real Estate [Member] | Post Massachusetts Avenue [Member]
Real Estate Properties [Line Items]
Real Estate Investments, Joint Ventures	$ 41,700		$ 41,700						$ 41,700
Maximum [Member] | Accounting Standards Update 2016-02 [Member]
Real Estate Properties [Line Items]
Operating lease, term of contract	1 year		1 year
Development Properties [Member] | Scenario Forecast [Member]
Real Estate Properties [Line Items]
Number of Real Estate Properties | Property					1	1	4	2
Retail [Member]
Real Estate Properties [Line Items]
Number of Real Estate Properties | Property	35		35
M A A L P [Member]
Real Estate Properties [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest			97.50%	97.40%
Limited Partnership [Member]
Real Estate Properties [Line Items]
General Partners' Capital Account, Units Outstanding | shares	117,071,410		117,071,410						116,883,421
Number of Real Estate Properties | Property	1		1
Development and capital improvements in progress	$ 484,955		$ 484,955						$ 470,282
Consolidated assets	11,835,597		11,835,597						11,812,369
Consolidated liabilities	5,745,216		5,745,216						5,664,724
Net proceeds from sale of marketable equity securities			0	$ 6,729
Limited Partnership [Member] | Real Estate [Member] | Variable Interest Entity Primary Beneficiary [Member]
Real Estate Properties [Line Items]
Consolidated assets	508,900		508,900						432,200
Consolidated liabilities	$ 26,000		$ 26,000						$ 27,100
Limited Partnership [Member] | Minimum [Member]
Real Estate Properties [Line Items]
Percentage of ownership interests of all consolidated subsidiaries (percent)	80.00%		80.00%
Limited Partnership [Member] | Maximum [Member]
Real Estate Properties [Line Items]
Percentage of ownership interests of all consolidated subsidiaries (percent)	100.00%		100.00%
Limited Partnership [Member] | Development Properties [Member] | Costs Incurred To Date [Member]
Real Estate Properties [Line Items]
Development and capital improvements in progress	$ 616,300		$ 616,300