Commitments and Contingencies - Summary of Properties Under Contracts (Details) ft² in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) ft² a property
Third-party seller
Real Estate Properties [Line Items]
Number of Buildings | property	1
Area of real estate property | ft²	13
Purchase price	$ 5,700
Assumed debt	$ 0
Improved land parcels
Real Estate Properties [Line Items]
Number of Buildings | property	21
Area of real estate property | a	82.2
Los Angeles | Third-party seller
Real Estate Properties [Line Items]
Number of Buildings | property	0
Area of real estate property | ft²	0
Purchase price	$ 0
Assumed debt	$ 0
Northern New Jersey/New York City | Third-party seller
Real Estate Properties [Line Items]
Number of Buildings | property	0
Area of real estate property | ft²	0
Purchase price	$ 0
Assumed debt	$ 0
San Francisco Bay Area | Third-party seller
Real Estate Properties [Line Items]
Number of Buildings | property	0
Area of real estate property | ft²	0
Purchase price	$ 0
Assumed debt	$ 0
Seattle | Third-party seller
Real Estate Properties [Line Items]
Number of Buildings | property	1
Area of real estate property | ft²	13
Purchase price	$ 5,700
Assumed debt	$ 0
Miami | Third-party seller
Real Estate Properties [Line Items]
Number of Buildings | property	0
Area of real estate property | ft²	0
Purchase price	$ 0
Assumed debt	$ 0
Washington D.C. | Third-party seller
Real Estate Properties [Line Items]
Number of Buildings | property	0
Area of real estate property | ft²	0
Purchase price	$ 0
Assumed debt	$ 0