COWLITZ PROJECT (Details) $ in Millions		3 Months Ended	6 Months Ended	12 Months Ended
	Dec. 04, 2015 USD ($)	Mar. 31, 2016 USD ($)	Mar. 31, 2016 USD ($)	Sep. 30, 2014 gaming_facility gaming_machine table_game	Sep. 30, 2015 USD ($)	Dec. 31, 2006 a
Schedule of Long-term Development Projects [Line Items]
Development fees		$ 1.3	$ 5.8
Cowlitz Project | Salishan-Mohegan
Schedule of Long-term Development Projects [Line Items]
Development fee			3.00%
Area of land purchased (in acres) | a						152
Term of management agreement			7 years
Management fee				24.00%
Number of authorized gaming facilities | gaming_facility				2
Number of authorized gaming machines, leasing | gaming_machine				975
Number of authorized gaming machines, operation | gaming_machine				3,000
Number of authorized table games, operation | table_game				125
Salishan-Mohegan Accounts Receivables | Affiliates
Schedule of Long-term Development Projects [Line Items]
Receivables and accrued interest		75.8	$ 75.8		$ 90.7
Reserve for doubtful collections		$ 15.2	$ 15.2		$ 21.2
Salishan-Mohegan | Cowlitz Project | Affiliates
Schedule of Long-term Development Projects [Line Items]
Proceeds from Collection of Long-term Loans to Related Parties	$ 19.4
Notes receivable term			7 years
Additional interest rate (as a percent)	1.00%
Financing rate (as a percent)	12.50%