Quarterly report pursuant to Section 13 or 15(d)

Unsecured Lines of Credit Payable (Details)

v2.4.0.6
Unsecured Lines of Credit Payable (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2012
Y
Mar. 31, 2012
Credit Facility No. 1 [Member]
     
Line of Credit Facility [Line Items]      
Committed capacity $ 100.0 $ 100.0 $ 75.0
Line of credit facility option to increase facility size through accordion feature 200.0 200.0  
Line of credit facility, expiration date 2015-June    
Line of credit extension term (in years)   1  
Debt instrument, basis spread on variable rate 107.50% 107.50%  
Borrowings outstanding (74.0) (74.0)  
Letters of credit issued (0.8) (0.8)  
Unused and available 25.2 25.2  
Balance, March 31, 2012 74.0    
Borrowings 0    
Repayments 0    
Balance, June 30, 2012 74.0 74.0  
Credit Facility No. 2 [Member]
     
Line of Credit Facility [Line Items]      
Committed capacity 400.0 400.0  
Line of credit facility, expiration date 2016-July    
Line of credit extension term (in years)   1  
Debt instrument, basis spread on variable rate 107.50% 107.50%  
Borrowings outstanding (147.0) (147.0)  
Letters of credit issued 0 0  
Unused and available 253.0 253.0  
Balance, March 31, 2012 35.0    
Borrowings 117.0    
Repayments (5.0)    
Balance, June 30, 2012 $ 147.0 $ 147.0