Summary of Significant Accounting Policies (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	1 Months Ended	12 Months Ended						12 Months Ended					12 Months Ended
	Jul. 31, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Retama Partners	Jan. 31, 2011 River Downs	Dec. 31, 2012 Heartland Poker Tour	Dec. 31, 2012 Allowance for Doubtful Accounts	Dec. 31, 2011 Allowance for Doubtful Accounts	Dec. 31, 2010 Allowance for Doubtful Accounts	Dec. 31, 2012 Ameristar	Apr. 02, 2013 Ameristar	Dec. 31, 2012 Ameristar Senior Notes Due 2021 [Member]
Basis of Presentation and Organization
Cost of Acquired Entity, Per Share											$ 26.50
Cost of Acquired Entity											$ 2,800,000,000
Business Acquisition, Estimated Related Fees and Expenses											1,000,000,000
Line of Credit Facility, Maximum Borrowing Capacity											1,400,000,000	1,400,000,000
Line of Credit Facility, Increase, Additional Borrowings		(47,500,000)	(99,000,000)	(165,379,000)							190,000,000
Stated percentage													7.50%
Note redeemable at a percentage of par													101.00%
Credit Facility, Increase of Borrwing Capacity		405,000,000
Issuance of New Senior Notes											315,000,000
Business Acquisition, Termination Fee											85,000,000
Business Acquisition, Percentage					75.50%
Balance Sheet Related Disclosures
Cash and cash equivalents		101,792,000	78,597,000
Allowance for doubtful accounts		7,526,000	4,718,000
Bad debt expense								3,876,000	2,908,000	1,144,000
Restricted cash		5,667,000	6,451,000
Indemnification trust deposit		5,700,000
Goodwill and Indefinite-lived Intangible Assets
Goodwill acquired						35,800,000	2,600,000
Business Acquisition, Contratual rights					50.00%
Impairment of indefinite-lived intangible assets		0	0	11,500,000
Accrued Liabilities
Self insurance accruals		16,500,000	14,800,000
Customer Loyalty Program Liability		11,500,000	10,800,000
Stock Repurchase Program, Authorized Amount	100,000,000
Treasury Stock, Shares, Acquired		4.4
Payments for Treasury Shares		51,000,000	0	0
Prior Period Reclassification Adjustment		$ 11,400,000	$ 10,200,000