Real Estate Investments and Related Intangibles - Property Acquisitions (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) property	Mar. 31, 2017 USD ($) property land_parcels
Acquisitions 2018 [Member]
Business Acquisition [Line Items]
Number of properties acquired | property	12
Total purchase price of assets acquired	$ 139,882
Capitalized acquisition costs	$ 700
2017 Acquisitions [Member]
Business Acquisition [Line Items]
Number of properties acquired | property		16
Number of land parcels acquired | land_parcels		3
Total purchase price of assets acquired		$ 101,914
Capitalized acquisition costs		$ 400