Segment Reporting - Summary of Financial Results by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Revenues:
Total revenues	$ 200,162	$ 48,904	$ 462,072	$ 79,687
Expenses:
Total expenses	90,605	22,606	205,811	35,249
Income from real estate-related securities	28,647	4,026	59,279	7,435
Segment net operating income	138,204	30,324	315,540	51,873
Depreciation and amortization	103,758	40,359	262,708	65,145
Other income (expense):
General and administrative	(3,027)	(1,716)	(7,973)	(5,969)
Management fee	(11,823)	(3,712)	(28,073)	(3,712)
Performance participation allocation	(12,447)	(5,711)	(29,796)	(10,952)	$ (17,000)
Interest income	82	36	280	418
Interest expense	(65,711)	(10,866)	(146,943)	(16,413)
Other income (expense)	(283)	157	(672)	85
Net loss	(58,763)	(31,847)	(160,345)	(49,815)
Net loss attributable to non-controlling interests	1,096	122	4,648	122
Net loss attributable to BREIT stockholders	(57,667)	(31,725)	(155,697)	(49,693)
Rental Property [Member]
Revenues:
Total revenues	134,567	33,599	323,334	55,727
Expenses:
Total expenses	63,783	15,938	153,853	25,632
Tenant Reimbursement Income [Member]
Revenues:
Total revenues	18,271	3,230	42,879	5,503
Hotel [Member]
Revenues:
Total revenues	40,000	9,874	79,017	15,048
Expenses:
Total expenses	26,822	6,668	51,958	9,617
Other Revenue [Member]
Revenues:
Total revenues	7,324	2,201	16,842	3,409
Multifamily [Member]
Revenues:
Total revenues	100,185	28,057	240,612	44,323
Expenses:
Total expenses	46,196	12,588	112,775	19,473
Segment net operating income	53,989	15,469	127,837	24,850
Depreciation and amortization	62,929	32,606	166,983	51,205
Multifamily [Member] | Rental Property [Member]
Revenues:
Total revenues	88,799	24,911	213,512	39,466
Expenses:
Total expenses	46,196	12,588	112,775	19,473
Multifamily [Member] | Tenant Reimbursement Income [Member]
Revenues:
Total revenues	5,049	964	11,463	1,472
Multifamily [Member] | Other Revenue [Member]
Revenues:
Total revenues	6,337	2,182	15,637	3,385
Industrial [Member]
Revenues:
Total revenues	56,630	9,780	134,644	18,066
Expenses:
Total expenses	16,818	3,029	38,681	5,664
Segment net operating income	39,812	6,751	95,963	12,402
Depreciation and amortization	31,966	5,408	77,786	9,852
Industrial [Member] | Rental Property [Member]
Revenues:
Total revenues	43,719	7,737	104,206	14,357
Expenses:
Total expenses	16,818	3,029	38,681	5,664
Industrial [Member] | Tenant Reimbursement Income [Member]
Revenues:
Total revenues	12,746	2,036	30,095	3,703
Industrial [Member] | Other Revenue [Member]
Revenues:
Total revenues	165	7	343	6
Hotel [Member]
Revenues:
Total revenues	40,781	9,874	79,798	15,048
Expenses:
Total expenses	26,822	6,668	51,958	9,617
Segment net operating income	13,959	3,206	27,840	5,431
Depreciation and amortization	7,633	1,862	14,643	3,119
Hotel [Member] | Hotel [Member]
Revenues:
Total revenues	40,000	9,874	79,017	15,048
Expenses:
Total expenses	26,822	6,668	51,958	9,617
Hotel [Member] | Other Revenue [Member]
Revenues:
Total revenues	781		781
Retail [Member]
Revenues:
Total revenues	2,566	1,193	7,018	2,250
Expenses:
Total expenses	769	321	2,397	495
Segment net operating income	1,797	872	4,621	1,755
Depreciation and amortization	1,230	483	3,296	969
Retail [Member] | Rental Property [Member]
Revenues:
Total revenues	2,049	951	5,616	1,904
Expenses:
Total expenses	769	321	2,397	495
Retail [Member] | Tenant Reimbursement Income [Member]
Revenues:
Total revenues	476	230	1,321	328
Retail [Member] | Other Revenue [Member]
Revenues:
Total revenues	41	12	81	18
Real Estate-Related Securities [Member]
Expenses:
Income from real estate-related securities	28,647	4,026	59,279	7,435
Segment net operating income	$ 28,647	$ 4,026	$ 59,279	$ 7,435