Significant Transactions (Details Textual) $ in Thousands				3 Months Ended		9 Months Ended
	Dec. 31, 2020 USD ($) apartment_home	Sep. 08, 2020 USD ($) apartment_home Multi_family_apartment $ / Home	Apr. 20, 2020 USD ($)	Sep. 30, 2020 USD ($) Property apartment_home	Sep. 30, 2019 USD ($) Property	Sep. 30, 2020 USD ($) Property apartment_home	Sep. 30, 2019 USD ($) Property apartment_home
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain on dispositions of real estate				$ 0	$ 1,146	$ 47,204	$ 356,929
IQHQ [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Commitment purchase amount				$ 50,000
Term Loan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Secured term loan			$ 350,000
Term loan maturity date			Apr. 20, 2021
Term loan option to extend			1 year
Variable interest rate description			currently bears interest at a 30-day LIBOR plus 1.85%, with a 50-basis point LIBOR floor.
Term Loan [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			1.85%
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			0.50%
Wholly And Partially Owned Consolidated Properties [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of apartment communities | Property				122		122
Number of apartment homes in apartment communities | apartment_home				33,067		33,067
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Scenario Forecast [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Sales price for a property to be sold	$ 126,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Wholly And Partially Owned Consolidated Properties [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of apartment communities sold | Property				0	0	1	8
Number of apartment homes sold | apartment_home						219	2,605
Gain on dispositions of real estate						$ 47,200	$ 356,900
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Scenario Forecast [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of apartment homes in apartment communities | apartment_home	266
Joint Venture Transaction
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of apartment communities | Multi_family_apartment		12
Number of apartment homes in apartment communities | apartment_home		4,051
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures		$ 2,400,000
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures | $ / Home		592,000
Secured term loan		$ 1,220,000
Implied equity value contributed by communities		1,180,000
Property debt		475,000
Investment owned amount		$ 461,000
Joint Venture Transaction | Ownership Exchanged [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Joint venture ownership percentage		39.00%
Joint Venture Transaction | Ownership Retained [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Joint venture ownership percentage retained		61.00%