Real Estate - Summary of Dispositions (Detail) ft² in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) ft² Property	Dec. 31, 2018 USD ($) ft² Property	Dec. 31, 2017 USD ($) ft² Property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total gains on other dispositions of investments in real estate, net	$ 157,841	$ 59,379	$ 27,254	$ 145,767	$ 217,035	$ 86,009	$ 30,592	$ 37,543	$ 390,241	$ 371,179	$ 855,437
Discontinuing Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total gains on dispositions of development properties and land, net									$ 467,577	$ 469,817	$ 327,528
Discontinuing Operations [Member] | Contributions to unconsolidated co-investment ventures [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of buildings | Property									26	36	29
Square feet | ft²									8,676	12,230	10,049
Net proceeds									$ 1,328,858	$ 1,459,963	$ 1,394,403
Gains on contributions, dispositions, revaluations or redemptions, net									$ 402,922	$ 422,540	$ 310,869
Discontinuing Operations [Member] | Dispositions to Third Parties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of buildings | Property									5	8	6
Square feet | ft²									1,351	3,297	2,322
Net proceeds									$ 204,197	$ 343,277	$ 290,679
Gains on contributions, dispositions, revaluations or redemptions, net									$ 64,655	$ 47,277	$ 16,659
Continuing Operations | Contributions to unconsolidated co-investment ventures [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of buildings | Property									19	4	193
Square feet | ft²									8,212	885	38,122
Net proceeds									$ 840,906	$ 51,466	$ 1,807,583
Gains on contributions, dispositions, revaluations or redemptions, net									$ 98,062	$ 36,567	$ 536,165
Continuing Operations | Dispositions to Third Parties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of buildings | Property									47	70	104
Square feet | ft²									7,604	12,150	14,825
Net proceeds									$ 651,306	$ 905,210	$ 990,822
Gains on contributions, dispositions, revaluations or redemptions, net									157,157	334,612	258,052
Continuing Operations | Revaluation of equity investments upon acquisition of controlling interest and redemption of investment in co-investment ventures [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gains on contributions, dispositions, revaluations or redemptions, net									0	0	61,220
Continuing Operations | Partial redemptions of investments in co-investment ventures [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gains on contributions, dispositions, revaluations or redemptions, net									$ 135,022	$ 0	$ 0