Real Estate Disposition Activities (Details) ft² in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) community home residential_condominium ft²	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) community home residential_condominium ft²	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Summary of income from discontinued operations
Gain on sale of communities	$ 35,295	$ 20,530	$ 59,731	$ 35,365
Number Of Communities Held For Sale | community	0		0
Number of Residential Condominium Units Sold | residential_condominium	16		52
Gain (Loss) on Sale of Other Investments			$ 7,446	0
Other Selling, General and Administrative Expense	$ 1,196	$ 945	2,639	$ 1,418
For-sale condominium inventory	311,236		$ 311,236		$ 457,809
Avalon Shelton [Member]
Summary of income from discontinued operations
Number Of Apartment Homes Sold | home			250
Proceeds from Sale of Real Estate			$ 64,750
Gain on sale of communities			$ 24,413
Avalon Tinton Falls [Member]
Summary of income from discontinued operations
Number Of Apartment Homes Sold | home			216
Proceeds from Sale of Real Estate			$ 64,900
Gain on sale of communities			35,297
The Park Loggia [Member]
Summary of income from discontinued operations
Proceeds from Sale of Real Estate	$ 61,207		$ 166,814
Number Of Residential Condominium Units | home	172		172
Retail Square Feet | ft²	67		67
Gain (Loss) on Sale of Other Investments	$ 2,544		$ 7,447