Real Estate - Summary of Purchase Price Allocation of Properties Acquired (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2018
Real Estate [Line Items]
Land	$ 473,709	$ 473,709	$ 350,470
In-place lease valuation (above market)	45,398	45,398	42,736
In-place lease valuation (below market)	(67,622)	(67,622)	$ (55,147)
2019 Revenue	80,300	212,800
Mergers
Real Estate [Line Items]
Land	135,875	135,875
Building	850,811	850,811
Improvements	62,928	62,928
Tenant origination and absorption costs	214,428	214,428
In-place lease valuation (above market)	3,627	3,627
In-place lease valuation (below market)	(12,476)	(12,476)
Land Leasehold Value Above Market	0	0
Total	1,255,193	1,255,193
2019 Revenue		44,124
McKesson II (3)
Real Estate [Line Items]
Land	0	0
Building	25,446	25,446
Improvements	4,681	4,681
Tenant origination and absorption costs	11,513	11,513
In-place lease valuation (above market)	239	239
In-place lease valuation (below market)	0	0
Land Leasehold Value Above Market	(3,072)	(3,072)
Total	$ 38,807	38,807
2019 Revenue		$ 107