Real Estate Investments and Related Intangibles - Property Acquisitions (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2020 USD ($) property	Mar. 31, 2019 USD ($) property	Sep. 30, 2019 property
Acquisitions, 2020 [Member]
Business Acquisition [Line Items]
Number of properties acquired | property	25
Total purchase price of assets acquired	$ 147,121
Capitalized acquisition costs	$ 900
Acquisitions, 2019 [Member]
Business Acquisition [Line Items]
Number of properties acquired | property		8
Total purchase price of assets acquired		$ 81,084
Capitalized acquisition costs		$ 300
Build-to-suit Development Project [Member] | Acquisitions, 2020 [Member]
Business Acquisition [Line Items]
Number of real estate properties acquired | property	1		1
Capitalized acquisition costs	$ 300
Development in process	19,300
Development in process, remaining committed investments	$ 25,500