Schedule III - Real Estate and Accumulated Depreciation (Parenthetical) (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) Property ApartmentUnit	Dec. 31, 2016 USD ($)
Real Estate And Accumulated Depreciation [Line Items]
Furniture, fixtures and equipment	$ 1,548,961,000	$ 1,346,300,000
Land and depreciable property net	$ 14,800,000,000	$ 15,800,000,000
Real Estate And Accumulated Depreciation Abstract
Total properties | Property	305
Apartment units | ApartmentUnit	78,611
Partially Owned Properties – Unconsolidated
Real Estate And Accumulated Depreciation Abstract
Total properties | Property	2
Apartment units | ApartmentUnit	945
Depreciable Property [Member]
Real Estate And Accumulated Depreciation [Line Items]
Furniture, fixtures and equipment	$ 1,548,960,951
Building [Member]
Real Estate And Accumulated Depreciation Abstract
Property, Plant and Equipment, Estimated Useful Lives	30 years
Renovations and Improvements Minimum [Member]
Real Estate And Accumulated Depreciation Abstract
Property, Plant and Equipment, Estimated Useful Lives	5 years
Renovations and Improvements Maximum [Member]
Real Estate And Accumulated Depreciation Abstract
Property, Plant and Equipment, Estimated Useful Lives	15 years
Replacements Minimum [Member]
Real Estate And Accumulated Depreciation Abstract
Property, Plant and Equipment, Estimated Useful Lives	5 years
Replacements Maximum [Member]
Real Estate And Accumulated Depreciation Abstract
Property, Plant and Equipment, Estimated Useful Lives	10 years
Management Business Renovations and Improvements Minimum [Member] [Member]
Real Estate And Accumulated Depreciation Abstract
Property, Plant and Equipment, Estimated Useful Lives	3 years
Management Business Renovations and Improvements Maximum [Member] [Member]
Real Estate And Accumulated Depreciation Abstract
Property, Plant and Equipment, Estimated Useful Lives	7 years