Significant Transactions (Details Textual) $ / shares in Units, shares in Thousands, $ in Thousands				1 Months Ended	3 Months Ended			9 Months Ended
	Jul. 15, 2021 USD ($)	Apr. 23, 2021 USD ($) $ / shares shares	Apr. 14, 2021 USD ($)	Oct. 31, 2021 USD ($) ft² ApartmentHome Multi_family_apartment	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($) ApartmentHome $ / shares	Sep. 30, 2020 ApartmentHome	Sep. 30, 2021 USD ($) ApartmentHome $ / shares	Sep. 30, 2020 USD ($) ApartmentHome	Dec. 31, 2020 USD ($) $ / shares
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Revolving credit facility borrowings						$ 78,200		$ 78,200		$ 265,600
Area of office and commercial space | ft²				84,000
Number of apartment homes in apartment communities				1,748		58	219	58	219
Purchase price				$ 510,000
Non Refundable Deposits								$ 32,200
Secured Debt						$ 3,013,913		3,013,913		$ 3,628,236
Gain (Loss) on Disposition of Assets						$ 7,100		$ 7,100	$ 47,200
Apartment Communities Expected to be Sold | ApartmentHome								15
Apartment Communities Sold | ApartmentHome						1	0	1
Proceeds From Issuance OP Units				128,000
Common Stock, par value (in dollars per share) | $ / shares						$ 0.01		$ 0.01		$ 0.01
Subsequent Event [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from Sale of Real Estate				$ 408,000	$ 470,000
Percentage of ownership sold to affiliate				80.00%
Subsequent Event [Member] | Affiliate of Blackstone [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
General partner ownership percentage				20.00%
Class A Common Stock [Member] | Private Placement [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Share issued and sold | shares		7,825
Common Stock, par value (in dollars per share) | $ / shares		$ 43.766
Cash purchase price received		$ 342,200
Prepayment Penalties on Debt Repayment		33,800
Revolving Credit Facility [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Revolving credit facility borrowings			$ 1,400,000			$ 78,200		$ 78,200
Credit facility, closing payment amount			950,000
Credit agreement option to increase maximum borrowing capacity								1.50%
Revolving credit facility			$ 600,000	$ 122
Variable interest rate description			30-day LIBOR plus 0.90%					30-day LIBOR plus 1.00%
Line of credit facility, expiration date			Apr. 14, 2025
Revolving credit facility right to extend term			two six-month extension
Line of credit facility maximum borrowing capacity						$ 517,800		$ 517,800
Revolving Credit Facility [Member] | 30-Day LIBOR [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Spread on variable interest rate			0.90%
Variable Rate Term Loan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Secured Debt			$ 800,000
Term Loan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Repayment of Debt			$ 350,000
Secured term loan	$ 350,000
Spread on variable interest rate	0.00%
Variable interest rate description	30-day LIBOR plus 0.95%
Line of credit facility, expiration date	Jul. 14, 2022
Revolving credit facility right to extend term	six month extension
Effective interest rate on outstanding borrowings						1.60%		1.60%
Term Loan [Member] | LIBOR Floor [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Spread on variable interest rate			0.00%
Property Debt [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Secured Debt				$ 259,000
Repayment of Property Debt		$ 318,400	$ 213,000
Debt, Weighted Average Interest Rate		4.60%
Apartment Community [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of apartment homes | ApartmentHome				1,400
Credit Agreement One [Member] | Term Loan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Revolving credit facility			$ 150,000
Line of credit facility, expiration date			Dec. 15, 2023
Revolving credit facility right to extend term			two one-year extension
Credit Agreement Two [Member] | Term Loan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Revolving credit facility			$ 300,000
Line of credit facility, expiration date			Dec. 15, 2024
Revolving credit facility right to extend term			one-year extension
Credit Agreement Three [Member] | Term Loan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Revolving credit facility			$ 150,000
Line of credit facility, expiration date			Dec. 15, 2025
Credit Agreement Four [Member] | Term Loan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Revolving credit facility			$ 200,000
Line of credit facility, expiration date			Apr. 14, 2026