Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule Of Significant Accounting Policies [Line Items]
Consolidation percentage if not wholly owned but controlled									less than 100% of the equity
Percentage of occupancy for stabilization									90.00%
Period after completion of construction for commencement of depreciation									1 year
Estimated useful lives									40 years
Weighted average lease term period									66 months
Depreciation commencement description									Depreciation on development buildings commences when the asset is ready for its intended use, which we define as the earlier of stabilization (90% occupied) or one year after completion of construction.
Threshold percentage to recognize gain or loss on transactions in consolidated entities	100.00%								100.00%
Percentage of taxable income distribute									100.00%
Rental	$ 723,857	$ 710,465	$ 700,689	$ 696,807	$ 679,195	$ 608,974	$ 544,679	$ 555,943	$ 2,831,818	$ 2,388,791	$ 2,225,141
Rental Revenue [Member]
Schedule Of Significant Accounting Policies [Line Items]
Rental										1,900,000	1,700,000
Rental Recoveries [Member]
Schedule Of Significant Accounting Policies [Line Items]
Rental										529,900	487,300
Other Assets [Member]
Schedule Of Significant Accounting Policies [Line Items]
Capitalized cost										$ 21,200	$ 23,800
Capital Improvements [Member] | Minimum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives									5 years
Capital Improvements [Member] | Maximum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives									7 years
Standard Tenant Improvements [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives									10 years
Depreciable and Land Improvements [Member] | Minimum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives									15 years
Depreciable and Land Improvements [Member] | Maximum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives									25 years
Operating Properties [Member] | Minimum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives									25 years
Operating Properties [Member] | Maximum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives									35 years