Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Nov. 09, 2020
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	000-56050
Entity Registrant Name	KBS GROWTH & INCOME REIT, INC.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	47-2778257
Entity Address, Address Line One	800 Newport Center Drive, Suite 700
Entity Address, City or Town	Newport Beach,
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92660
City Area Code	949
Local Phone Number	417-6500
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	false
Entity Central Index Key	0001631256
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Ex Transition Period	true
Class A Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		9,873,729
Class T Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		310,974