Leases - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) Property CorporateOfficeLease	Dec. 31, 2018	Jan. 01, 2019 USD ($)
Operating Leased Assets [Line Items]
Percentage of rental income	100.00%	100.00%
Lease liabilities	$ 331,334		$ 278,287
Right-of-use assets	$ 512,774		$ 434,201
Corporate Office Leases [Member]
Operating Leased Assets [Line Items]
Number of operating leases | CorporateOfficeLease	9
Number of office lease modified | CorporateOfficeLease	4
Lease liabilities	$ 43,105
Right-of-use assets	$ 41,596
Ground Leases [Member]
Operating Leased Assets [Line Items]
Unsecured borrowing rates for actual pricing period used for calculating discount rate	30 years
Lease liabilities	$ 264,990
Right-of-use assets	$ 413,196
Number of operating properties | Property	14
Finance lease, liability	$ 23,239
Finance lease,ROU asset	57,982
Modified Corporate Office leases [Member]
Operating Leased Assets [Line Items]
Lease liabilities	32,100
Right-of-use assets	32,100
Ground Lease Under Development [Member]
Operating Leased Assets [Line Items]
Finance lease, liability	23,200
Finance lease,ROU asset	$ 57,900
Maximum [Member] | Corporate Office Leases [Member]
Operating Leased Assets [Line Items]
Discount rate	3.90%
Remaining lease terms	10 years
Lease expiration dates (inclusive of applicable extension options)	2042
Maximum [Member] | Ground Leases [Member]
Operating Leased Assets [Line Items]
Discount rate	5.50%
Operating lease expiration year	2118
Minimum [Member] | Corporate Office Leases [Member]
Operating Leased Assets [Line Items]
Discount rate	3.30%
Lease expiration dates (inclusive of applicable extension options)	2021
Minimum [Member] | Ground Leases [Member]
Operating Leased Assets [Line Items]
Discount rate	4.40%
Operating lease expiration year	2042
Residential Apartment Leases [Member]
Operating Leased Assets [Line Items]
Percentage of rental income	97.00%
Residential Apartment Leases [Member] | Maximum [Member]
Operating Leased Assets [Line Items]
Retail leases term	12 months
Retail Commercial Leases [Member]
Operating Leased Assets [Line Items]
Percentage of rental income	3.00%
Retail Commercial Leases [Member] | Maximum [Member]
Operating Leased Assets [Line Items]
Retail leases term	10 years
Retail Commercial Leases [Member] | Minimum [Member]
Operating Leased Assets [Line Items]
Retail leases term	5 years