Summary of Significant Accounting Policies - Schedule of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($)
$ in Thousands
Mar. 31, 2018
Dec. 31, 2017
Mar. 31, 2017
Dec. 31, 2016
Restricted Cash and Cash Equivalents Items [Line Items]        
Cash and cash equivalents $ 10,989 $ 8,798 $ 9,309  
Total cash, cash equivalents and restricted cash 128,154 114,707 52,683 $ 36,898
Collateral deposits        
Restricted Cash and Cash Equivalents Items [Line Items]        
Restricted cash 1,190 1,751 1,451  
Tenant improvements, repairs, and leasing commissions        
Restricted Cash and Cash Equivalents Items [Line Items]        
Restricted cash 8,782 8,257 10,277  
Master Trust Release        
Restricted Cash and Cash Equivalents Items [Line Items]        
Restricted cash 97,010 85,703 30,395  
Liquidity reserve        
Restricted Cash and Cash Equivalents Items [Line Items]        
Restricted cash 5,527 5,503 0  
Other        
Restricted Cash and Cash Equivalents Items [Line Items]        
Restricted cash $ 4,656 $ 4,695 $ 1,251