Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Nov. 05, 2020
Entity Information [Line Items]
Document Type	10-Q
Document Period End Date	Sep. 30, 2020
Entity Registrant Name	Cole Office & Industrial REIT (CCIT III), Inc.
Entity Current Report Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Amendment Flag	false
Entity Central Index Key	0001614976
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Class A Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		2,500,000
Class T Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		709,000