Subsequent Events (Details) - USD ($)
$ in Thousands
1 Months Ended 12 Months Ended
Feb. 28, 2017
Feb. 01, 2017
Jul. 14, 2015
Jan. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Feb. 27, 2017
Subsequent Event [Line Items]                
Proceeds from mortgage financing         $ 266,970 $ 170,233 $ 92,791  
Repayments of secured debt         177,469 121,267 $ 51,309  
Non-recourse mortgage loans         170,900 170,200    
Line of credit outstanding         49,751 $ 112,834    
Revolver                
Subsequent Event [Line Items]                
Line of credit outstanding         $ 50,000      
WPC | LIBOR                
Subsequent Event [Line Items]                
Basis spread     1.10%          
Subsequent Event                
Subsequent Event [Line Items]                
Repayments of secured debt $ 42,900 $ 92,400            
Non-recourse mortgage loans   $ 105,000            
Subsequent Event | LIBOR                
Subsequent Event [Line Items]                
Basis spread   1.75%            
Subsequent Event | Revolver                
Subsequent Event [Line Items]                
Line of credit outstanding               $ 33,800
Subsequent Event | Hellweg 2 | Net Lease                
Subsequent Event [Line Items]                
Proceeds from mortgage financing       $ 89,000        
Subsequent Event | Hellweg 2 | WPC | Net Lease                
Subsequent Event [Line Items]                
Proceeds from mortgage financing       $ 243,800