Noncontrolling Interests In Subsidiaries (Tables)
 3 Months Ended
Mar. 31, 2012
Noncontrolling Interests In Subsidiaries [Abstract]  
Changes Of Noncontrolling Interests In Subsidiaries
 
Common
 
Units
Balance at January 1, 2012
12,197,122
Redemption of common units for shares of common stock
(10,000)
   
Balance at March 31, 2012
12,187,122