Real Estate - Acquisitions (Details) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended
	May 31, 2019	Jun. 30, 2019	Jun. 30, 2018
Real Estate Properties [Line Items]
Acquisitions of real estate assets	$ 56,700	$ 129,856	$ 3,390
Net Lease Asset
Real Estate Properties [Line Items]
Acquisitions of real estate assets		11,500
Leasehold Interest
Real Estate Properties [Line Items]
Acquisitions of real estate assets		$ 98,200
SAFE
Real Estate Properties [Line Items]
Ground lease term (in years)		98 years