Investment In Real Estate Joint Ventures And Partnerships (Schedule Of Combined Condensed Statements Of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule of Equity Method Investments [Line Items]
Revenues, net	$ 112,355			$ 121,362			$ 321,842	$ 367,160
Expenses
Depreciation and amortization	37,946			33,380			112,229	102,319
Interest, net	15,044			13,820			45,422	44,062
Operating	22,816			22,912			65,954	69,927
Real estate taxes, net	16,479			15,205			47,220	47,072
General and administrative	10,245			8,432			25,472	26,893
Provision for income taxes	195			21			710	682
Gain on dispositions	10,268			74,115			31,742	143,963
Net Income	27,461	$ 12,377	$ 54,248	108,509	$ 85,520	$ 51,254	94,086	245,283
Joint Ventures and Limited Partnerships
Schedule of Equity Method Investments [Line Items]
Revenues, net	32,073			33,853			92,629	99,245
Expenses
Depreciation and amortization	8,803			7,914			26,467	23,409
Interest, net	2,328			2,336			7,080	7,286
Operating	5,579			6,035			18,152	17,820
Real estate taxes, net	4,333			4,891			12,948	13,948
General and administrative	92			110			430	422
Provision for income taxes	30			34			100	103
Total	21,165			21,320			65,177	62,988
Gain on dispositions	178			0			46,967	2,009
Net Income	$ 11,086			$ 12,533			$ 74,419	$ 38,266