Organization and Business Purpose - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2017 USD ($) Investment Position Segment shares	Dec. 31, 2016 shares
Organization and business activities.
Date of formation	Nov. 16, 2015
Common stock, shares authorized, amount | $	$ 5,000,000,000
Common stock, shares issued	125,491,201
Number of real estate investments | Investment	18
Number of reportable segments | Segment	5
Commercial Mortgage Backed Securities [Member]
Organization and business activities.
Number of positions | Position	24
Class S Shares [Member]
Organization and business activities.
Common stock, shares issued	98,779,308	0
Class I Shares [Member]
Organization and business activities.
Common stock, shares issued	23,277,430	20,000
Class T Shares [Member]
Organization and business activities.
Common stock, shares issued	2,208,763	0
Class D Shares [Member]
Organization and business activities.
Common stock, shares issued	1,225,700	0
IPO [Member]
Organization and business activities.
Common stock, shares authorized, amount | $	$ 4,000,000,000
Distribution Reinvestment Plan [Member]
Organization and business activities.
Common stock, shares authorized, amount | $	$ 1,000,000,000