Annual report pursuant to Section 13 and 15(d)

DEBT FINANCING - Narrative (Details)

v3.3.1.900
DEBT FINANCING - Narrative (Details)
3 Months Ended 9 Months Ended 12 Months Ended
Aug. 13, 2015
USD ($)
financial_institution
component
Apr. 01, 2014
USD ($)
financial_institution
Dec. 31, 2015
USD ($)
property
Sep. 30, 2015
USD ($)
property
Jun. 30, 2015
USD ($)
property
Mar. 31, 2015
USD ($)
property
Dec. 31, 2014
USD ($)
property
Sep. 30, 2014
USD ($)
property
Jun. 30, 2014
USD ($)
property
Mar. 31, 2014
USD ($)
property
Dec. 31, 2013
USD ($)
Dec. 31, 2015
USD ($)
property
Dec. 31, 2014
USD ($)
property
Dec. 31, 2012
property
Debt Instrument [Line Items]                            
Repayment of long term debt                     $ 48,048,000 $ 357,273,000 $ 143,970,000  
Loss on debt extinguishment                     $ 0 414,000 344,000  
Debt financing     $ 570,612,000       $ 597,691,000         570,612,000 597,691,000  
Liabilities assumed, mortgages     $ 23,643,000 $ 2,866,000 $ 30,547,000 $ 16,442,000 $ 6,270,000 $ 59,546,000 $ 0 $ 0   $ 73,498,000 $ 65,816,000  
Number of self storage properties acquired with assumed mortgages | property     16 15 21 6 15 31 36 1   58 83 43
Line of Credit [Member] | Credit Facility [Member]                            
Debt Instrument [Line Items]                            
Number of financial institutions in lender agreement | financial_institution 11                          
Increase in total borrowing capacity $ 125,000,000.0                          
Total borrowing capacity $ 550,000,000.0                          
Number of lender agreement components | component 2                          
Line of Credit [Member] | Credit Facility [Member] | Revolving line of credit [Member]                            
Debt Instrument [Line Items]                            
Maximum borrowing capacity   $ 350,000,000.0 $ 162,025,000.000                 $ 162,025,000.000    
Borrowing base calculation, minimum occupancy rate of property   75.00%                        
Extension fee, percent                       0.20%    
Debt financing     187,975,000       $ 166,217,000         $ 187,975,000 $ 166,217,000  
Line of Credit [Member] | Credit Facility [Member] | Revolving line of credit [Member] | London Interbank Offered Rate (LIBOR) [Member]                            
Debt Instrument [Line Items]                            
Borrowing rate spread                       1.60%    
Line of Credit [Member] | Credit Facility [Member] | Revolving line of credit [Member] | Minimum [Member]                            
Debt Instrument [Line Items]                            
Unused borrowing capacity fee, percent   0.20%                        
Line of Credit [Member] | Credit Facility [Member] | Revolving line of credit [Member] | Maximum [Member]                            
Debt Instrument [Line Items]                            
Unused borrowing capacity fee, percent   0.25%                        
Line of Credit [Member] | Credit Facility [Member] | Term Loan [Member]                            
Debt Instrument [Line Items]                            
Maximum borrowing capacity   $ 200,000,000.0                        
Debt financing     200,000,000       144,558,000         $ 200,000,000 144,558,000  
Line of Credit [Member] | Credit Facility [Member] | Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]                            
Debt Instrument [Line Items]                            
Borrowing rate spread                       1.50%    
Line of Credit [Member] | Amended Credit Facility [Member]                            
Debt Instrument [Line Items]                            
Maximum borrowing capacity $ 700,000,000.0                          
Loans Payable [Member] | Unsecured Term Loan [Member]                            
Debt Instrument [Line Items]                            
Maximum borrowing capacity   $ 50,000,000.0                        
Number of lenders | financial_institution   3                        
Repayment of long term debt                       $ 50,000,000    
Loss on debt extinguishment                       200,000    
Debt financing     0       50,000,000         0 50,000,000  
Maturity date extension fee                       250,000    
Loans Payable [Member] | Unsecured Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]                            
Debt Instrument [Line Items]                            
Borrowing rate spread   5.00%                        
Mortgages [Member] | Fixed Rate Mortgages [Member]                            
Debt Instrument [Line Items]                            
Repayment of long term debt                       34,700,000    
Debt financing     182,637,000       153,416,000         $ 182,637,000 153,416,000  
Minimum effective interest rate                       2.20%    
Maximum effective interest rate                       5.00%    
Liabilities assumed, mortgages                       $ 73,500,000 $ 65,800,000  
Number of self storage properties acquired with assumed mortgages | property                       31 16  
Mortgages [Member] | Variable Rate Mortgages [Member]                            
Debt Instrument [Line Items]                            
Repayment of long term debt                       $ 83,500,000    
Loss on debt extinguishment                       200,000    
Debt financing     $ 0       $ 83,500,000         $ 0 $ 83,500,000  
Minimum effective interest rate                       2.43%    
Maximum effective interest rate                       9.65%    
Extinguishment of debt, prepayment penalty                       $ 500,000