Quarterly Financial Information (Unaudited) - Schedule of Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$ 596,840	$ 438,033	$ 354,308	$ 297,091	$ 261,186	$ 200,162	$ 152,226	$ 109,684	$ 78,245	$ 48,904	$ 28,339	$ 2,444	$ 1,686,272	$ 723,258	$ 157,932
Net loss	(184,869)	(126,494)	(52,784)	(50,096)	(131,120)	(58,763)	(51,944)	(49,638)	(37,735)	(31,847)	(16,701)	(1,267)	(414,243)	(291,465)	(87,550)
Net loss attributable to BREIT stockholders	$ (181,050)	$ (123,171)	$ (50,704)	$ (46,846)	$ (125,359)	$ (57,667)	$ (50,482)	$ (47,548)	$ (36,565)	$ (31,725)	$ (16,701)	$ (1,267)	$ (401,771)	$ (281,056)	$ (86,258)
Net loss per share of common stock — basic and diluted	$ (0.17)	$ (0.15)	$ (0.08)	$ (0.10)	$ (0.30)	$ (0.17)	$ (0.19)	$ (0.23)	$ (0.24)	$ (0.28)	$ (0.22)	$ (0.03)	$ (0.54)	$ (0.91)	$ (0.90)