Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 27, 2020	Jun. 30, 2019
Entity Information [Line Items]
Entity Registrant Name	Griffin Capital Essential Asset REIT, Inc.
Entity Central Index Key	0001600626
Document Type	10-K
Document Period End Date	Dec. 31, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Small Business	false
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Public Float			$ 0
Common Class T
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		551,959
Common Class S
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		1,797
Common Class D
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		40,379
Common Class I
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		1,847,480
Common Class A
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		24,190,291
Common Class AA
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		46,979,600
Common Class AAA
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		917,024
Common Class E
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		155,033,020