Related Party Transactions - Property Management and Servicing Agreement (Details) - USD ($)
$ in Thousands
12 Months Ended
May 20, 2014
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Related Party Transaction [Line Items]        
Related party fee income   $ 15,838 $ 0 $ 0
Affiliated Entity | Property management        
Related Party Transaction [Line Items]        
Annual management fees rate 0.25%      
Related party fee income   3,700    
Affiliated Entity | Special servicing fees        
Related Party Transaction [Line Items]        
Annual management fees rate 0.75%      
Related party fee income   500    
Affiliated Entity | Property Management and Servicing Agreement        
Related Party Transaction [Line Items]        
Due from related parties   $ 500