Summary of Significant Accounting Policies - Schedule of Restricted Cash and Escrow Deposits (Details) - USD ($)
$ in Thousands
Mar. 31, 2015
Dec. 31, 2014
Summary Of Significant Accounting Policies [Line Items]    
Restricted cash and investments $ 62,276 $ 100,344
Collateral Deposits    
Summary Of Significant Accounting Policies [Line Items]    
Restricted cash and investments 29,783 29,483
Tenant Improvements, Repairs and Leasing Commissions    
Summary Of Significant Accounting Policies [Line Items]    
Restricted cash and investments 13,130 13,427
Master Trust Release    
Summary Of Significant Accounting Policies [Line Items]    
Restricted cash and investments 9,658 53,069
Title Company Escrow    
Summary Of Significant Accounting Policies [Line Items]    
Restricted cash and investments 6,937 0
Loan Impounds    
Summary Of Significant Accounting Policies [Line Items]    
Restricted cash and investments 671 794
Other Restricted Cash and Escrow Deposits    
Summary Of Significant Accounting Policies [Line Items]    
Restricted cash and investments $ 2,097 $ 3,571