Commitments and Contingencies (Details) (USD $)	3 Months Ended								12 Months Ended						1 Months Ended	12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012 item	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Belle of Sioux City, L.P. (the "Belle") item sqft	Dec. 31, 2012 Breach in pre-development agreement Kansas Penn Gaming, LLC item	Sep. 11, 2008 Breach in pre-development agreement Kansas Penn Gaming, LLC	Sep. 30, 2008 Breach in pre-development agreement Kansas Penn Gaming, LLC Minimum	Dec. 31, 2012 Pending Litigation Argosy Casino Sioux City facility Belle of Sioux City, L.P. (the "Belle")
Litigation
Lawsuits filed against IRGC												3
Number of proposals submitted to the IRGC for a new gaming and entertainment destination												2
Size of casino floor (in square foot)												33,000
Number of slot machines												750
Number of table games												20
Number of table poker rooms												5
Number of hotel rooms												150
Goodwill and other intangible assets																$ 92,800,000
Net revenues	743,811,000	707,044,000	712,551,000	736,059,000	676,450,000	710,905,000	687,879,000	667,023,000	2,899,465,000	2,742,257,000	2,459,111,000					57,100,000
Income from operations	73,293,000	98,666,000	128,015,000	142,615,000	105,919,000	130,335,000	140,592,000	122,735,000	442,589,000	499,581,000	153,226,000					16,600,000
Net revenues, percentage																2.00%
Income from operations, percentage																4.00%
Damages sought value															50,000,000
Privilege fee paid in conjunction with the gaming application for the Cherokee County zone														25,000,000
Accruals related to settlement included in accrued expenses													6,400,000
Number of parties to the settlement agreement													2
Operating Lease Commitments
Total rental expense under agreements									29,700,000	28,900,000	30,500,000
Revenue sharing provision as a percentage of gross slot revenue under the lease agreement									3.00%
Initial term of lease									15 years
Number of lease renewal options									3
Term of lease renewal options									10 years
Future minimum lease commitments relating to the base lease rent portion of noncancelable operating leases
2013	7,456,000								7,456,000
2014	5,201,000								5,201,000
2015	3,768,000								3,768,000
2016	3,142,000								3,142,000
2017	2,605,000								2,605,000
Thereafter	32,104,000								32,104,000
Total	54,276,000								54,276,000
Capital Expenditure Commitments
Capital expenditures under current construction program for 2012	259,600,000								259,600,000
Contractual commitment to spend on capital expenditures	$ 20,800,000								$ 20,800,000