Significant Transactions - Summarized Information Regarding Acquisition (Details) $ in Thousands	Aug. 25, 2020 USD ($) apartment_home	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Business Acquisition [Line Items]
Land		$ 1,891,763	$ 1,869,048
Buildings and improvements		$ 7,006,395	$ 6,868,543
Asset Acquisitions [Member]
Business Acquisition [Line Items]
Number of apartment homes in apartment communities | apartment_home	271
Purchase price	$ 89,600
Capitalized transaction costs	2,506
Total consideration	92,106
Land	56,251
Buildings and improvements	34,645
Consideration allocated to intangible assets	1,506
Consideration allocated to below-market lease liabilities	$ (296)