Annual report pursuant to Section 13 and 15(d)

Unsecured Lines Of Credit Payable (Narrative) (Details)

v2.4.0.6
Unsecured Lines Of Credit Payable (Narrative) (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Line of Credit Facility [Line Items]      
Line Of Credit Extension Term 1    
Committed capacity $ 475,000 $ 337,000 $ 337,000
Credit Facility No. 1 [Member]
     
Line of Credit Facility [Line Items]      
Line of Credit Facility, Expiration Date 2012-June    
Committed capacity 75,000    
Credit Facility No. 2 [Member]
     
Line of Credit Facility [Line Items]      
Line of Credit Facility, Expiration Date 2014-July    
Committed capacity $ 400,000