Commitments and Contingencies - Narrative (Details)
6 Months Ended
Jun. 30, 2019
USD ($)
tenant
claim
ground_lease
Dec. 31, 2018
USD ($)
Commitments And Contingencies Disclosure [Abstract]    
Contingently liable amount of debt owed by tenant $ 5,700,000 $ 5,700,000
Number of tenants indemnified by | tenant 1  
Accruals made for environmental remediation $ 0  
Outstanding claims | claim 0  
Total commitments $ 71,400,000  
Total commitments relating to future acquisitions 38,700,000  
Commitments to purchase capital assets within one year expected to be funded within one year $ 50,700,000  
Operating lease renewal option two  
Operating lease renewal term 5 years  
Number of long-term non-cancelable ground leases | ground_lease 4  
Operating lease, weighted average remaining lease term 8 years 1 month 6 days  
Operating lease, weighted average discount rate 4.26%  
Incentive to lessee $ 1,700,000  
Operating lease, right-of-use assets $ 5,900,000