Summary of significant accounting policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Accounting Policies [Line Items]
Restricted Cash and Cash Equivalents, Current	$ 5,925,000	$ 5,925,000
Accounts Receivable, Gross, Current	5,800,000	8,800,000
Gaming Receivables, Gross, Current	1,200,000	4,000,000
Allowance for Doubtful Accounts Receivable, Current	400,000	1,400,000
Interest Costs, Capitalized During Period	500,000	700,000	9,000,000
Impairment of Capitalized Design Costs	200,000	200,000	3,800,000
Complimentary Departmental Costs	71,004,000	66,931,000	69,342,000
Players' club rewards	16,038,000	13,882,000
Advertising Expense	30,300,000	26,100,000	27,600,000
Weighted Average Number of Shares Outstanding, Basic	40,242,000	58,025,000	57,543,000
Weighted Average Number Diluted Shares Outstanding Adjustment	894,000	793,000	0
Weighted Average Number of Shares Outstanding, Diluted	41,136,000	58,818,000	57,543,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,500,000	3,300,000	3,200,000
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets, Gross	5,600,000
Progressive jackpot liability cumulative adjustment	3,412,000
Food and Beverage [Member]
Accounting Policies [Line Items]
Complimentary Departmental Costs	54,575,000	50,276,000	50,003,000
Rooms [Member]
Accounting Policies [Line Items]
Complimentary Departmental Costs	13,556,000	11,669,000	12,681,000
Entertainment [Member]
Accounting Policies [Line Items]
Complimentary Departmental Costs	679,000	2,517,000	3,026,000
Other Dept [Member]
Accounting Policies [Line Items]
Complimentary Departmental Costs	$ 2,194,000	$ 2,469,000	$ 3,632,000
Furniture, Fixtures and Equipment [Member]
Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life, Minimum	3
Property, Plant and Equipment, Useful Life, Maximum	10
Building and Building Improvements [Member]
Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life, Minimum	5
Property, Plant and Equipment, Useful Life, Maximum	40