BASIS OF PRESENTATION - Share-based Compensation, Additional Cash Flow Information and New Accounting Standards (Details) - USD ($)		1 Months Ended	3 Months Ended		9 Months Ended
	Jul. 01, 2017	Jul. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Debt Instrument [Line Items]
Share-based compensation expense			$ 0	$ 0	$ 7,600,000	$ 6,100,000
Decrease in cash and cash equivalents					(3,766,000)	(122,607,000)
Payments of tender offer and repurchase costs					50,308,000	0
Payments of discounts					25,455,000	7,348,000
Early Adoption Effect | Accounting Standards Update 2016-15
Debt Instrument [Line Items]
Payments of tender offer and repurchase costs					50,300,000
Payments of discounts					15,500,000
Prior Senior Secured Credit Facility, Term Loan A and B | Senior Secured Credit Facility
Debt Instrument [Line Items]
Reduction in notes payable					18,649,000	5,179,000
Decrease in cash and cash equivalents		$ 5,200,000
2012 Mohegan Tribe Promissory Note | Promissory Notes
Debt Instrument [Line Items]
Reduction in notes payable					$ 0	$ 6,000,000
Subsequent Event | Prior Senior Secured Credit Facility, Term Loan A and B | Senior Secured Credit Facility
Debt Instrument [Line Items]
Decrease in cash and cash equivalents	$ 18,600,000