Investments in Unconsolidated Entities - Summarized Balance Sheet with Reconciliation To Equity Investment In Unconsolidated Entities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule Of Equity Method Investments [Line Items]
Total assets	$ 40,684,015	$ 33,039,823
Total liabilities	(24,470,008)	(22,404,026)
Total equity	16,183,951	$ 10,614,648	$ 3,914,954	$ 1,509,639
Investments in unconsolidated entities	816,220
BREIT MGP JV [Member]
Schedule Of Equity Method Investments [Line Items]
Investments in unconsolidated entities	816,220
BREIT MGP JV [Member] | Equity Method Investment [Member]
Schedule Of Equity Method Investments [Line Items]
Total assets	4,618,979
Total liabilities	(3,002,080)
Total equity	1,616,899
BREIT MGP JV [Member] | BREIT's Share [Member]
Schedule Of Equity Method Investments [Line Items]
Investments in unconsolidated entities	806,833
BREIT MGP JV [Member] | BREIT Outside Basis [Member]
Schedule Of Equity Method Investments [Line Items]
Investments in unconsolidated entities	9,387
BREIT MGP JV [Member] | MGM Growth Properties LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Investments in unconsolidated entities	$ 810,066