Investments in Unconsolidated Entities - Summarized Balance Sheet with Reconciliation To Equity Investment In Unconsolidated Entities (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Schedule Of Equity Method Investments [Line Items]
Total assets	$ 36,628,499		$ 33,039,823
Total liabilities	(22,037,333)		(22,404,026)
Total equity	14,569,513	$ 13,815,602	$ 10,614,648	$ 6,376,375	$ 4,591,704	$ 3,914,954
Investments in unconsolidated entities	811,827
BREIT MGP JV [Member]
Schedule Of Equity Method Investments [Line Items]
Investments in unconsolidated entities	811,827
BREIT MGP JV [Member] | Equity Method Investment [Member]
Schedule Of Equity Method Investments [Line Items]
Total assets	4,609,419
Total liabilities	(3,001,469)
Total equity	1,607,950
BREIT MGP JV [Member] | BREIT's Share [Member]
Schedule Of Equity Method Investments [Line Items]
Investments in unconsolidated entities	802,367
BREIT MGP JV [Member] | BREIT Outside Basis [Member]
Schedule Of Equity Method Investments [Line Items]
Investments in unconsolidated entities	9,460
BREIT MGP JV [Member] | MGM Growth Properties LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Investments in unconsolidated entities	$ 805,583