v2.4.0.6
Income Taxes (Unrecognized Tax Benefits) (Details) (USD $)
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]        
Unrecognized tax benefit, beginning of year   $ 42,320,000 $ 38,336,000 $ 29,053,000
Tax positions related to consolidation of Borgata 0 0 8,714,000  
Tax positions related to current year 1,468,000 1,438,000 1,511,000  
Tax positions related to prior years 15,456,000 3,718,000 0  
Tax positions related to prior years (10,969,000) (1,172,000) (918,000)  
Settlement with taxing authorities (9,852,000) 0 0  
Lapse of applicable statute of limitations 0 0 (24,000)  
Unrecognized tax benefits 38,423,000 42,320,000 38,336,000  
Income tax penalties and interest expense (200,000) 2,400,000 2,000,000  
Income tax penalties and interest accrued 12,400,000 12,600,000    
Decreases in unrecognized tax benefits resulting from settlements with taxing authorities, portion which affected effective tax rate 100,000      
Interest expense resulting from income tax examination 4,000,000      
Income tax expense (benefit) resulting from income tax examination settlement 2,600,000      
Estimated decrease in recognized tax beneifts over next 12 months, minimum 1,200,000      
Estimated decrease in recognized tax beneifts over next 12 months, maximum 22,600,000      
Significant change in unrecognized tax benefits is reasonably possible that would impact effective tax rate 1,100,000      
Internal Revenue Service (IRS)
        
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]        
Unrecognized tax benefits that would impact effective tax rate $ 6,700,000