XML 18 R37.htm IDEA: XBRL DOCUMENT v2.4.0.6
Related Party Transactions (Details) (USD $)
9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Dec. 31, 2011
Treasury Stock Purchases from Related Party (Textual) [Abstract]      
Treasury stock, shares 1,242,262   1,134,528
Treasury stock $ 33,825,000   $ 31,120,000
Related Party Transactions (Additional Textual) [Abstract]      
Repurchase interests of partners and trust unit holders 66,000 192,000  
Board of Directors [Member]
     
Treasury Stock Purchases from Related Party (Textual) [Abstract]      
Treasury stock, shares 45,179    
Treasury stock $ 1,130,000