LONG-TERM DEBT - Schedule of Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Sep. 30, 2015	Aug. 31, 2013	Mar. 31, 2013	Mar. 31, 2012
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	$ 1,697,140	$ 1,666,344
Less: current portion of long-term debt	(31,300)	(55,194)
Long-term debt, net of current portion	1,665,840	1,611,150
Credit Facility | Senior Secured Credit Facility - Revolving, due June 2018
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	19,000	21,000
Credit Facility | Senior Secured Credit Facility - Term Loan A, due June 2018, net of discount and debt issuance costs of $1,700 and $2,106 as of June 30, 2016 and September 30, 2015, respectively
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	98,288	109,613
Unamortized discount and debt issuance costs	1,700	2,106
Credit Facility | Senior Secured Credit Facility - Term Loan B, due June 2018, net of discount and debt issuance costs of $12,679 and $14,918 as of June 30, 2016 and September 30, 2015, respectively
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	765,495	792,078
Unamortized discount and debt issuance costs	12,679	14,918
Credit Facility | Downs Lodging Credit Facility, due July 2016, net of debt issuance costs of $254 as of September 30, 2015
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	0	40,262
Unamortized discount and debt issuance costs		254
Credit Facility | New Downs Lodging Credit Facility, due November 2019, net of debt issuance costs of $1,376 as of June 30, 2016
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	22,062	0
Unamortized discount and debt issuance costs	1,376
Senior Unsecured Notes | 2013 9 3/4% Senior Unsecured Notes, due September 2021, net of premium and debt issuance costs of $6,727 and $7,333 as of June 30, 2016 and September 30, 2015, respectively
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	578,273	577,667
Unamortized discount and debt issuance costs	$ 6,727	$ 7,333
Note stated interest rate	9.75%	9.75%	9.75%
Senior Unsecured Notes | 2015 Senior Unsecured Notes, due December 2017, net of debt issuance costs of $2,014 as of June 30, 2016
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	$ 97,986	$ 0
Unamortized discount and debt issuance costs	2,014
Senior Subordinated Notes | 2012 11 % Senior Subordinated Notes, due September 2018, net of discount and debt issuance costs of $973 and $1,251 as of June 30, 2016 and September 30, 2015, respectively
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	99,217	98,939
Unamortized discount and debt issuance costs	$ 973	$ 1,251
Note stated interest rate	11.00%	11.00%			11.00%
Promissory Notes | 2012 Mohegan Tribe Minor's Trust Promissory Note, due March 2017
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	$ 7,000	$ 16,000
Note stated interest rate	12.50%				10.00%
Promissory Notes | 2013 Mohegan Tribe Promissory Note, due December 2018
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	$ 7,420	7,420
Note stated interest rate				4.00%
Other
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	$ 2,399	$ 3,365