Related Party Transactions - Schedule of Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	$ 911	$ 8,892	$ 0
Receivable as of December 31,	1,411	837
Incurred for the Year Ended December 31,	15,037	25,244	45,084
Payable as of December 31,	3,272	10,883
Deferred Compensation and Other Payroll Costs [Member]
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	0	658	0
Receivable as of December 31,	0	0
Operating expenses
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	0	0	3,594
Payable as of December 31,	0	0
Asset management fees
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	0	0	23,668
Payable as of December 31,	0	0
Property management fees
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	0	0	9,479
Payable as of December 31,	0	0
Disposition fees
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	0	641	177
Payable as of December 31,	0	0
Costs advanced by the advisor
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	2,000	3,771	546
Payable as of December 31,	1,085	1,164
Consulting fee - shared services
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	2,500	2,500	0
Payable as of December 31,	695	441
Acquisition fees
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	0	942	5,331
Payable as of December 31,	0	0
Leasing commissions
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	0	2,540	2,289
Payable as of December 31,	0	0
Earn-out
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	0	0	0
Payable as of December 31,	262	2,919
Other Fees
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	243	0	0
Receivable as of December 31,	293	352
Incurred for the Year Ended December 31,	0	20	0
Payable as of December 31,	0	0
Stockholder Servicing Fee
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	0	692	0
Payable as of December 31,	494	4,994
Distributions
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	10,537	14,138	0
Payable as of December 31,	736	1,365
Griffin Capital Corporation | Payroll/Expense Allocation
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	15	4	0
Receivable as of December 31,	4	4
Griffin Capital Corporation | Payroll/Expense Allocation
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	653	481	0
Receivable as of December 31,	1,114	481
Griffin Capital Essential Asset REIT II | Payroll/Expense Allocation
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	0	1,217	0
Receivable as of December 31,	0	0
Griffin Capital Essential Asset REIT II | O&O Costs (including payroll allocated to O&O)
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	0	157	0
Receivable as of December 31,	0	0
Griffin Capital Essential Asset REIT II | Other Fees
Related Party Transaction [Line Items]
Incurred for the Year Ended December 31,	0	6,375	$ 0
Receivable as of December 31,	$ 0	$ 0