Investments in Joint Ventures (Aggregate Balance Sheet And Statement Of Income Data For Unconsolidated Joint Ventures) (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2020		Sep. 30, 2019	Sep. 30, 2020		Sep. 30, 2019	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Fees earned for property and asset management, construction, development, and other services to joint ventures		$ 1,900		$ 1,700	$ 5,700		$ 4,600
Assets		7,324,723			7,324,723			$ 6,748,504
Liabilities		3,758,716			3,758,716			3,046,780
Equity		3,494,063			3,494,063			3,628,685
Net income		36,220		44,782	98,198		128,045
Income (Loss) from Equity Method Investments		2,200	[1],[2]	2,100	5,909	[1],[2]	5,954
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Schedule of Equity Method Investments [Line Items]
Assets		697,300			697,300			685,000
Liabilities		507,200			507,200			496,900
Equity		155,500			155,500			$ 153,400
Revenues	[3]	32,700		33,300	95,800		98,500
Net income		$ 4,300		$ 4,400	$ 11,700		$ 12,300

[1] Equity in income for the nine months ended September 30, 2020 includes our ownership interest of the Resident Relief Funds payments of approximately $0.4 million.

[2] Equity in income excludes our ownership interest of fee income from various services provided by us to the Funds.

[3] Total revenues for the nine months ended September 30, 2020 includes approximately $1.3 million of Resident Relief Funds payments which was recorded as a reduction to property revenues.