COMMITMENTS AND CONTINGENCIES (Details)	2 Months Ended	10 Months Ended	12 Months Ended
	Sep. 30, 2016 USD ($)	Jul. 31, 2016	Sep. 30, 2016 USD ($) gaming_facility slot_machine	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
Mohegan Tribe
Commitments and Contingencies [Line Items]
Term of lease			25 years
Renewable period of additional term			25 years
Mohegan Basketball Club | WNBA
Commitments and Contingencies [Line Items]
Membership or limited partnership interest (as a percent)			4.20%
Slot Win Contributions
Commitments and Contingencies [Line Items]
Contribution frequency period			12 months
Contribution determination criteria 1, percent of gross revenues from slot machines, lesser of			30.00%
Contribution determination criteria 2a, lesser of, percent of gross revenues from slot machines, greater of			25.00%
Contribution determination criteria 2b, lesser of, set cash contribution			$ 80,000,000.0
Contribution rate applied to excess free promotional play revenues in excess of limitation, if other than standard rate			25.00%
Limitation of excluded free promotional play as a percent of gross revenues from slot machines			11.00%
Slot win contributions			$ 148,100,000	$ 145,600,000	$ 146,500,000
Slot win contributions outstanding	$ 12,300,000		$ 12,300,000	11,900,000
Pennsylvania Slot Machine Tax
Commitments and Contingencies [Line Items]
Tax rate applied to percent of gross revenues from slot machines			55.00%
Portion of taxed revenues subject to minimum annual local share assessment			2.00%
Minimum annual local share assessment			$ 10,000,000.0
Escrow deposit for tax payments	1,500,000.0		1,500,000.0
Slot machine tax expense recognized			122,300,000	119,600,000	122,300,000
Slot machine tax expense, outstanding	$ 4,800,000		$ 4,800,000	4,700,000
Pennsylvania Slot Machine Tax | Downs Racing
Commitments and Contingencies [Line Items]
Number of slot machines at Mohegan Sun at Pocono Downs permitted by license | slot_machine			3,000
Number of slot machines at Mohegan Sun at Pocono Downs permitted by license expandable to | slot_machine			5,000
Pennsylvania Table Game Tax
Commitments and Contingencies [Line Items]
Subsequent table game tax rate	14.00%	12.00%
Additional local tax	2.00%	2.00%
Table game tax expense recognized			$ 6,400,000	6,700,000	6,300,000
Table game tax expense outstanding	$ 93,000		93,000	148,000
Pennsylvania Regulatory Fee
Commitments and Contingencies [Line Items]
Fee rate, percent of gross revenues from slot machines and table games	1.70%	1.50%
Regulatory fee recognized			4,800,000	4,600,000	4,700,000
Regulatory fee outstanding	$ 112,000		112,000	70,000
Pennsylvania Gaming Control Board Loans
Commitments and Contingencies [Line Items]
Loans obtained by PGCB			36,100,000
Additional Loans granted by PGCB			$ 63,800,000
Number of authorized gaming facilities | gaming_facility			14
Number of authorized gaming facilities that have commenced operations | gaming_facility			12
PGCB loan repayment period			10 years
PGCB loan repayment expense			$ 623,000	620,000	638,000
Horsemen's Agreement
Commitments and Contingencies [Line Items]
Purses earned by horsemen and other fees outstanding	$ 5,000,000		5,000,000	5,500,000
Priority Distribution Agreement
Commitments and Contingencies [Line Items]
Annual initial amount of priority distribution payments			40,000,000
Priority distribution payments			40,000,000	$ 31,500,000	$ 19,500,000
Town of Montville Agreement
Commitments and Contingencies [Line Items]
Annual payments			$ 500,000
Land Lease Agreement
Commitments and Contingencies [Line Items]
Rental fee, percent of annual revenues for periods not occupied by primary tenant			8.00%
Land Lease Agreement | Mohegan Tribe
Commitments and Contingencies [Line Items]
Term of lease			25 years
Renewable period of additional term			25 years