Commitments and Contingencies - Narrative (Details) $ in Thousands		12 Months Ended
	Feb. 06, 2020 USD ($) a ft² property letter contract	Dec. 31, 2019 USD ($) ft² a property land_parcel
Other Commitments [Line Items]
Number of properties		220
Area of real estate property | a		77.6
Improved land parcels [Member]
Other Commitments [Line Items]
Number of properties | land_parcel		19
Area of real estate property | ft²		13,300,000
Third-party seller [Member]
Other Commitments [Line Items]
Number of properties		1
Area of real estate property | ft²		65,670
Asset acquisitions, assets acquired and liabilities assumed, net | $		$ 30,000
Third-party seller [Member] | Washington D.C. [Member]
Other Commitments [Line Items]
Number of properties		0
Area of real estate property | ft²		0
Asset acquisitions, assets acquired and liabilities assumed, net | $		$ 0
Subsequent event [Member] | Third-party seller [Member]
Other Commitments [Line Items]
Outstanding contracts with a third-party | contract	2
Subsequent event [Member] | Third-party seller [Member] | Industrial property [Member]
Other Commitments [Line Items]
Number of properties	1
Area of real estate property | ft²	66,000
Subsequent event [Member] | Third-party seller [Member] | Improved land parcels [Member]
Other Commitments [Line Items]
Number of properties	1
Area of real estate property | a	2.78
Subsequent event [Member] | Third-Party seller, non-binding letter [Member] | Senior Secured Loan Receivable [Member] | Washington D.C. [Member]
Other Commitments [Line Items]
Number of non-binding letters of intent | letter	1
Subsequent event [Member] | Third-Party seller, non-binding letter [Member] | Industrial property [Member] | Washington D.C. [Member]
Other Commitments [Line Items]
Number of properties	3
Area of real estate property | ft²	340,000
Asset acquisitions, assets acquired and liabilities assumed, net | $	$ 54,000