Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019
Significant Of Accounting Policies [Line Items]
Assets excluding BREIT OP	$ 33,039,823,000	$ 13,237,158,000
Liabilities excluding BREIT OP	22,404,026,000	9,312,971,000
Subscriptions received in advance, common stock	$ 787,700,000	166,500,000
Percentage of taxable income distributed to stockholders	100.00%
Deferred benefit	$ 3,100,000	1,500,000	$ 300,000
Tax expense	2,200,000	900,000	0
Operating lease, ROU assets	114,011,000
Operating lease, liabilities	82,880,000
Account Standards Update 2016-02
Significant Of Accounting Policies [Line Items]
Ground leases discount rate				7.00%
Operating lease, ROU assets				$ 31,300,000
Operating lease, liabilities				31,300,000
Prepaid ground lease intangible asset reclassified as ROU operating asset				15,700,000
Below-market ground lease intangible asset reclassified as ROU operating asset	4,500,000
Above-market ground lease intangible liability reclassified as ROU operating asset	4,600,000
Straight-line ground rent liability reclassified as ROU operating asset	$ 1,200,000
Lease, practical expedients package	true
Lease, practical expedient, use of hindsight	false
Impact to retained earnings as a result of ASU adoption				$ 0
Rental revenue previously classified as tenant reimbursement income		64,100,000	11,000,000
Level 2 [Member]
Significant Of Accounting Policies [Line Items]
Investments in real estate debt	$ 4,500,000,000	2,300,000,000
Level 3 [Member]
Significant Of Accounting Policies [Line Items]
Mortgage notes, term loans, secured and unsecured revolving credit facilities, repurchase agreements, and affiliate line of credit	54,900,000	6,900,000
Hyatt Place Uc Davis [Member] | Other Assets [Member]
Significant Of Accounting Policies [Line Items]
Deferred tax assets	4,900,000	1,800,000	300,000
Hyatt Place Uc Davis [Member] | Other Income [Member]
Significant Of Accounting Policies [Line Items]
Net tax benefit	$ 900,000	600,000	300,000
Class T Shares [Member]
Significant Of Accounting Policies [Line Items]
Percentage of stockholder servicing fee on NAV per annum	0.85%
Selling commissions and dealer manager fees (% of transaction price)	3.50%
Upfront selling commissions and dealer manager fees (% of transaction price)	3.00%
Selling commissions and upfront dealer manager fees (% of transaction price)	0.50%
Advisor stockholder servicing fee (% of NAV)	0.65%
Dealer stockholder servicing fee (% of NAV)	0.20%
Class S Shares [Member]
Significant Of Accounting Policies [Line Items]
Percentage of stockholder servicing fee on NAV per annum	0.85%
Selling commissions and dealer manager fees (% of transaction price)	3.50%
Class D Shares [Member]
Significant Of Accounting Policies [Line Items]
Percentage of stockholder servicing fee on NAV per annum	0.25%
Selling commissions and dealer manager fees (% of transaction price)	1.50%
Class S Shares, Class D Shares and Class T Shares [Member]
Significant Of Accounting Policies [Line Items]
Stockholder servicing fees accrued	$ 478,500,000	238,500,000
Adviser [Member]
Significant Of Accounting Policies [Line Items]
Organizational and offering costs			$ 10,200,000
Period for reimbursement of advance expenses	60 months
Reimbursement of organization and offering costs	$ 2,000,000	2,000,000
Blackstone Advisory Partners L.P. [Member]
Significant Of Accounting Policies [Line Items]
Commission and fees, threshold percentage on gross proceeds from sale of share	8.75%
Blackstone Advisory Partners L.P. [Member] | Class T Shares [Member]
Significant Of Accounting Policies [Line Items]
Percentage of stockholder servicing fee on NAV per annum	0.85%
Blackstone Advisory Partners L.P. [Member] | Class S Shares [Member]
Significant Of Accounting Policies [Line Items]
Percentage of stockholder servicing fee on NAV per annum	0.85%
Blackstone Advisory Partners L.P. [Member] | Class D Shares [Member]
Significant Of Accounting Policies [Line Items]
Percentage of stockholder servicing fee on NAV per annum	0.25%
Blackstone Advisory Partners L.P. [Member] | Class I Shares [Member]
Significant Of Accounting Policies [Line Items]
Percentage of stockholder servicing fee on NAV per annum	0.00%
VIEs [Member]
Significant Of Accounting Policies [Line Items]
Assets excluding BREIT OP	$ 9,500,000,000	2,800,000,000
Liabilities excluding BREIT OP	$ 6,600,000,000	$ 1,900,000,000