Debt - CMBS - Narrative (Details)
$ in Thousands
Jun. 30, 2019
USD ($)
Property
loan
Dec. 31, 2018
USD ($)
Debt Instrument [Line Items]    
Unamortized deferred financing costs $ 17,681 $ 14,932
Weighted Average    
Debt Instrument [Line Items]    
Stated interest rate 3.96%  
CMBS    
Debt Instrument [Line Items]    
Number of loans secured by mortgage on leased properties and related assets | loan 6  
Number of properties securing borrowings | Property 100  
Unamortized deferred financing costs $ 2,900 3,200
Unamortized premium $ 100 $ 100
CMBS | Weighted Average    
Debt Instrument [Line Items]    
Stated interest rate 5.35%  
CMBS | Minimum    
Debt Instrument [Line Items]    
Stated interest rate 4.67%  
CMBS | Maximum    
Debt Instrument [Line Items]    
Stated interest rate 6.00%