LONG-TERM DEBT - Schedule of Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Sep. 30, 2014	Aug. 31, 2013	Mar. 31, 2013	Mar. 31, 2012	Sep. 30, 2009	Feb. 28, 2005
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	$ 1,679,449	$ 1,730,936
Less: current portion of long-term debt	(25,241)	(31,558)
Long-term debt, net of current portion	1,654,208	1,699,378
Credit Facility | Senior Secured Credit Facility - Revolving, due June 2018
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	8,000	37,000
Credit Facility | Senior Secured Credit Facility - Term Loan A, due June 2018, net of discount of $408 and $523, respectively
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	113,654	119,789
Unamortized discount	408	523
Credit Facility | Senior Secured Credit Facility - Term Loan B, due June 2018, net of discount of $6,780 and $8,337, respectively
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	712,270	716,188
Unamortized discount	6,780	8,337
Credit Facility | Line of Credit
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	0	3,041
Credit Facility | Downs Lodging Credit Facility, due July 2016
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	45,000	45,000
Senior Unsecured Notes | 2013 9 3/4% Senior Unsecured Notes, due September 2021
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	$ 500,000	$ 500,000
Note stated interest rate	9.75%	9.75%	9.75%
Senior Subordinated Notes | 2005 6 7/8% Senior Subordinated Notes, due February 2015
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	$ 0	$ 9,654
Note stated interest rate	6.875%	6.875%					6.875%
Senior Subordinated Notes | 2012 11 % Senior Subordinated Notes, due September 2018, net of discount of $2,957 and $3,506, respectively
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	$ 272,233	$ 271,684
Unamortized discount	$ 2,957	$ 3,506
Note stated interest rate	11.00%	11.00%			11.00%
Promissory Notes | 2009 Mohegan Tribe Promissory Note, due September 2015
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	$ 875	$ 1,750
Note stated interest rate						10.00%
Promissory Notes | 2012 Mohegan Tribe Minor's Trust Promissory Note, due March 2017
Debt Schedule [Abstract]
Long-term debt, excluding capital leases	16,500	16,500
Note stated interest rate					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	$ 3,497	$ 2,910