Investments in Real Estate - Narrative (Details) ft² in Thousands, $ in Thousands	3 Months Ended							6 Months Ended
	Jun. 30, 2020 USD ($) property	Jun. 30, 2020 property	Jun. 30, 2020 ft² property	Jun. 30, 2020 a property	Mar. 31, 2020 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Jun. 30, 2020 USD ($) property	Jun. 30, 2020 property	Jun. 30, 2020 ft² property	Jun. 30, 2020 a property	Jun. 30, 2019 USD ($) ft² a property	Jun. 30, 2020 ft²	Jun. 30, 2020 a
Finite-Lived Intangible Assets [Line Items]
Rental revenues and tenant expense reimbursements	$ 45,742					$ 41,730		$ 90,858				$ 82,610
Net income	30,704				$ 12,856	10,379	$ 15,532	43,560				25,911
Capitalized interest associated with redevelopment activities	$ (400)					(800)		$ (1,000)				(1,600)
Improved land parcels
Finite-Lived Intangible Assets [Line Items]
Number of properties | property	22	22	22	22				22	22	22	22
Square Feet | ft²													13,100
Redevelopment property
Finite-Lived Intangible Assets [Line Items]
Number of properties | property	2	2	2	2				2	2	2	2
Square Feet													500	85.0
Asset acquisition, consideration transferred								$ 97,000
Asset acquisition, real estate development costs								89,800
Asset Acquisitions 2020
Finite-Lived Intangible Assets [Line Items]
Purchase Price (in thousands)	$ 10,500							41,100
Finite-lived intangible assets acquired	300							1,300
Asset Acquisition, Intangible Liabilities	(100)							(600)
Rental revenues and tenant expense reimbursements	500							600
Net income	400							500
Asset Acquisitions 2020 | Industrial building
Finite-Lived Intangible Assets [Line Items]
Number of properties acquired | property		1							2
Area of real estate property acquired			13	2.8						79	5.5
Asset Acquisitions 2020 | Land
Finite-Lived Intangible Assets [Line Items]
Asset acquisition, property additions	9,000							30,900
Asset Acquisitions 2020 | Building
Finite-Lived Intangible Assets [Line Items]
Asset acquisition, property additions	$ 1,200							8,900
Asset Acquisitions 2019
Finite-Lived Intangible Assets [Line Items]
Purchase Price (in thousands)								51,200				119,400
Finite-lived intangible assets acquired								3,300				7,200
Asset Acquisition, Intangible Liabilities								(3,100)				(6,400)
Rental revenues and tenant expense reimbursements						$ 1,200						1,400
Net income								(600)				$ 700
Asset Acquisitions 2019 | Industrial building
Finite-Lived Intangible Assets [Line Items]
Number of properties acquired | property									2			4
Area of real estate property acquired | ft²										119		165
Asset Acquisitions 2019 | Improved land parcels
Finite-Lived Intangible Assets [Line Items]
Number of properties acquired | property												2
Area of real estate property acquired | a												19.7
Asset Acquisitions 2019 | Land
Finite-Lived Intangible Assets [Line Items]
Asset acquisition, property additions								34,800				$ 94,400
Asset Acquisitions 2019 | Building
Finite-Lived Intangible Assets [Line Items]
Asset acquisition, property additions								$ 13,100				$ 17,800