COMMITMENTS AND CONTINGENCIES (Details) (USD $)	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014	Sep. 30, 2014
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	34,300,000	34,700,000	70,800,000	71,000,000
Slot win contributions outstanding	12,800,000		12,800,000		11,600,000
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		1,500,000
Slot machine tax expense recognized	28,400,000	30,600,000	57,600,000	60,400,000
Slot machine tax expense, outstanding	1,900,000		1,900,000		4,600,000
Pennsylvania Slot Machine Tax | Downs Racing, L.P.
Commitments and Contingencies [Line Items]
Number of slot machines at Mohegan Sun at Pocono permitted by license			3,000
Permitted slot machine capacity (in slot machines)			5,000
Pennsylvania Table Game Tax
Commitments and Contingencies [Line Items]
Initial tax rate			12.00%
Additional local tax			2.00%
Table game tax expense recognized	1,800,000	1,500,000	3,400,000	3,000,000
Table game tax expense outstanding	198,000		198,000		156,000
Pennsylvania Regulatory Fee
Commitments and Contingencies [Line Items]
Fee rate, percent of gross revenues from slot machines and table games			1.50%
Regulatory fee recognized	1,100,000	1,200,000	2,200,000	2,300,000
Regulatory fee outstanding	171,000		171,000		147,000
Pennsylvania Gaming Control Board Loans
Commitments and Contingencies [Line Items]
Loans granted by PGCB			36,100,000
Additional Loans granted by PGCB			63,800,000
Number of authorized gaming facilities			14
Number of authorized gaming facilities that have commenced operations			12
PGCB loan repayment period			10 years
PGCB loan repayment expense	156,000	160,000	313,000	320,000
Horsemen's Agreement
Commitments and Contingencies [Line Items]
Purses earned by horsemen and other fees outstanding	6,700,000		6,700,000		8,100,000
Priority Distribution Agreement
Commitments and Contingencies [Line Items]
Annual limit of priority distribution payments			40,000,000
Priority distribution payments	$ 6,600,000	$ 4,900,000	$ 11,500,000	$ 9,700,000