v2.4.0.6
Commitments and Contingencies (Loss Contingency) (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended 1 Months Ended 12 Months Ended 1 Months Ended 12 Months Ended 12 Months Ended 12 Months Ended
Dec. 31, 2012
action
Aug. 31, 2008
Purse Enhancement Agreement
Dec. 31, 2012
Atlantic City
Feb. 28, 2009
County Assessor
Property Tax Assessment
Dec. 31, 2007
County Assessor
Property Tax Assessment
Dec. 31, 2011
County Assessor
Property Tax Assessment
Dec. 31, 2007
Borgata
Dec. 31, 2012
Borgata
Dec. 31, 2011
Borgata
Dec. 31, 2010
Borgata
Aug. 31, 2008
Borgata
Dec. 31, 2010
Borgata
Purse Enhancement Agreement
Dec. 31, 2012
Borgata
Purse Enhancement Agreement
property
Dec. 31, 2012
Borgata
Atlantic City
Dec. 31, 2011
Borgata
Atlantic City
Dec. 31, 2012
Borgata
New Jersey Casino Control Act
Investment Alternative Tax Assessment
Dec. 31, 2012
Borgata
CRDA
Investment Alternative Tax Assessment
Dec. 31, 2009
State of Nevada Department of Taxation
Sales and Use Tax Deficiency
Loss Contingencies [Line Items]                                    
Number of legal actions brought against company to date 2                                  
Amount of assessment by taxing authority         $ 6.2                         $ 12.3
Amount of interest assessed by taxing authority                                   7.5
Increase in assessed property value, percentage         400.00%                          
Amount of increase (decrease) of initial tax assessment by taxing authority       (2.2)                            
Property tax settlement, reduction in property tax accrual           9.7                        
Investment Alternative Tax:                                    
New Jersey annual investment alternative tax, percentage                               1.25% 2.50%  
Term of New Jersey Casino Reinvestment Development Authority (CRDA) bonds             20 years 50 years                    
New Jersey Casino Reinvestment Development Authority (CRDA) obligation               7.7 8.1 8.1                
New Jersey Casino Reinvestment Development Authority (CRDA) obligation, valuation provision recorded               4.4 3.5 4.6                
Purse Enhancement Agreement:                                    
Number of casinos participating in Purse Enhancement Agreement                         10          
Obligation of all participating casinos, total   90                                
Borgata's pro rata share of Purse Enhancement Agreement obligation                     15.0              
Atlantic City Tourism District [Abstract]                                    
Initial term of Atlantic City Alliance (ACA) assessment                           5 years        
ACA total five-year assessment by all casinos plus initial contribution     155                              
Atlantic City Alliance initial contribution     5                              
ACA annual assessment by all casinos     30                              
Expense under the agreement recorded in period                       $ 5.1   $ 6.1 $ 0.9