LONG-TERM DEBT - Schedule of Long-term Debt Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Sep. 30, 2017
Debt Schedule [Abstract]
Long-term debt	$ 1,824,380	$ 1,651,209
Less: current portion of long-term debt	(71,170)	(75,131)
Long-term debt, net of current portion	1,753,210	1,576,078
Credit Facility | Senior Secured Credit Facility - Revolving
Debt Schedule [Abstract]
Long-term debt	84,000	0
Credit Facility | Senior Secured Credit Facility - Term Loan A
Debt Schedule [Abstract]
Long-term debt	327,480	387,523
Discount and debt issuance costs	7,335	7,415
Credit Facility | Senior Secured Credit Facility - Term Loan B
Debt Schedule [Abstract]
Long-term debt	811,711	761,039
Discount and debt issuance costs	21,460	18,073
Credit Facility | Mohegan Expo Credit Facility
Debt Schedule [Abstract]
Long-term debt	31,899	13,017
Discount and debt issuance costs	1,400	1,683
Senior Unsecured Notes | 2016 7 7/8% Senior Unsecured Notes
Debt Schedule [Abstract]
Long-term debt	488,639	487,617
Discount and debt issuance costs	$ 11,361	$ 12,383
Note stated interest rate	7.875%	7.875%
Other
Debt Schedule [Abstract]
Long-term debt	$ 1,810	$ 2,013
Note Payable | Redemption Note Payable
Debt Schedule [Abstract]
Long-term debt	78,841	$ 0
Discount and debt issuance costs	$ 35,959