| 
           Feb. 25, 2009
 
          2003 Stock Incentive Plan [Member]
 
          Phantom Stock [Member] 
         | 
        
           Dec. 31, 2011
 
          2003 Stock Incentive Plan [Member]
 
          Phantom Stock [Member] 
         | 
        
           Dec. 31, 2010
 
          2003 Stock Incentive Plan [Member]
 
          Phantom Stock [Member] 
         | 
        
           Dec. 31, 2009
 
          2003 Stock Incentive Plan [Member]
 
          Phantom Stock [Member] 
         | 
        
           Dec. 31, 2011
 
          2003 Stock Incentive Plan [Member]
 
          Restricted Stock [Member] 
         | 
        
           Dec. 31, 2010
 
          2003 Stock Incentive Plan [Member]
 
          Restricted Stock [Member] 
         | 
        
           Dec. 31, 2009
 
          2003 Stock Incentive Plan [Member]
 
          Restricted Stock [Member] 
         | 
        
           Jun. 30, 2010
 
          2007 Retention Grants [Member]
 
          Restricted Stock [Member] 
         | 
        
           Dec. 01, 2009
 
          2007 Retention Grants [Member]
 
          Restricted Stock [Member] 
         | 
        
           Dec. 01, 2008
 
          2007 Retention Grants [Member]
 
          Restricted Stock [Member] 
         | 
        
           Jun. 30, 2011
 
          2011 Restricted Stock Awards [Member]
 
          Restricted Stock [Member] 
         | 
        
           Dec. 31, 2011
 
          One Year Graded Vesting Period [Member]
 
          2003 Stock Incentive Plan [Member]
 
          Restricted Stock [Member] 
         | 
        
           Dec. 31, 2011
 
          Vesting Period June 30, 2012 [Member]
 
          2011 Restricted Stock Awards [Member]
 
          Restricted Stock [Member] 
         | 
        
           Dec. 31, 2011
 
          Vesting Period June 30, 2013 [Member]
 
          2011 Restricted Stock Awards [Member]
 
          Restricted Stock [Member] 
         | 
        
           Dec. 31, 2011
 
          Three-year graded vesting period [Member]
 
          Phantom Stock [Member] 
         | 
        
           Dec. 31, 2011
 
          Three-year graded vesting period [Member]
 
          2003 Stock Incentive Plan [Member]
 
          Restricted Stock [Member] 
         | 
        
           Dec. 31, 2011
 
          Four-year graded vesting period [Member]
 
          2003 Stock Incentive Plan [Member]
 
          Restricted Stock [Member] 
         |