Annual report pursuant to Section 13 and 15(d)

Unsecured Line Of Credit And Term Notes (Details)

v2.4.0.6
Unsecured Line Of Credit And Term Notes (Details) (USD $)
12 Months Ended 0 Months Ended 12 Months Ended 12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Aug. 05, 2011
Maturity In August 2018 [Member]
Dec. 31, 2011
Maturity In August 2018 [Member]
Dec. 31, 2011
Maturity In August 2016 [Member]
Dec. 31, 2010
Maturity In August 2016 [Member]
Dec. 31, 2011
Maturity In August 2021 [Member]
Dec. 31, 2011
Maturity In June 2012 [Member]
Dec. 31, 2011
Maturity In September 2013 [Member]
Dec. 31, 2011
Maturity In September 2013 [Member]
Fixed Interest Rate [Member]
Dec. 31, 2011
Maturity In April 2016 [Member]
Dec. 31, 2011
Mortgage Notes Payable [Member]
Line of Credit Facility [Line Items]                          
Unsecured term note $ 575,000,000 $ 400,000,000   $ 125,000,000       $ 100,000,000 $ 150,000,000 $ 20,000,000 $ 80,000,000 $ 150,000,000  
Basis spread over LIBOR       2.00% 2.00% 2.00%       1.50%      
Revolving line of credit facility agreement 175,000,000                        
Revolving line of credit facility expandable amount 250,000,000                        
Facility fee           0.20%              
Amount available on unsecured line of credit           129,000,000              
Unsecured revolving line of credit, fees paid 4,146,000                          
Extension facility fee 0.125%                        
Additional secured commitments         $ 100,000,000                
Line of credit facility, maturity date range, Start                         December 2011
Interest rate on term loan               5.54%     6.26% 6.38%  
Increase in interest rate on term loan               7.29%       8.13%  
Interest rate, line of credit facility           2.28% 1.64%            
Line of credit facility, expiration date       August 2018 August 2018 August 2016   August 2021 June 2012 September 2013 September 2013 April 2016