v2.4.0.6
Summary of Significant Accounting Policies (Other) (Details) (USD $)
Share data in Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Accounting Policies [Abstract]      
Cash and cash equivalents, maturity of qualifying investments, maximum 3 months    
Restricted cash, maturity of qualifying investments, maximum 90 days    
Interest costs capitalized $ 1,000,000 $ 400,000 $ 0
Self Insurance Reserve [Roll Forward]      
Self insurance reserve, beginning balance 34,500,000 31,721,000 27,825,000
Additions      
Charged to costs and expenses 103,802,000 89,464,000 77,307,000
Due to consolidation of Borgata 0 0 15,544,000
Due to acquisitions 359,000 1,111,000 0
Payments made 99,998,000 87,796,000 88,955,000
Self insurance reserve, ending balance 38,663,000 34,500,000 31,721,000
Gaming taxes 270,300,000 258,400,000 256,500,000
Advertising expense 38,300,000 33,100,000 31,800,000
Corporate expense $ 50,719,000 $ 48,962,000 $ 48,861,000
Weighted average shares outstanding:      
Basic 87,652 87,263 86,601
Potential dilutive effect 0 0 230
Diluted 87,652 87,263 86,831