CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2019
Cash flows provided by (used in) operating activities:
Net income (loss)	$ (49,929)	$ 19,877	$ (180,536)	$ 18,301
Adjustments to reconcile net income (loss) to net cash flows provided by (used in) operating activities:
Depreciation and amortization	26,477	22,810	82,847	92,682
Non-cash operating lease expense			9,364
Accretion of discounts			857	864
Amortization of discounts and debt issuance costs			13,977	14,619
Provision for losses on receivables			2,676	962
Impairment of Mohegan Sun Pocono's intangible assets			126,596	0
Deferred income tax provision			(3,262)	0
Other, net			2,255	(26)
Changes in operating assets and liabilities, net of effect of the MGE Niagara Resorts acquisition:
Accounts receivable			1,237	(9,023)
Accrued interest on notes receivable related to the Cowlitz Project			0	71,696
Inventories			714	(269)
Due from Ontario Lottery and Gaming Corporation			5,482	0
Casino Operating and Services Agreement customer contract asset			(78,210)	0
Other assets			398	(6,901)
Trade payables			6,672	965
Accrued interest			(5,402)	(9,189)
Due to Ontario Lottery and Gaming Corporation			3,598	0
Operating lease liabilities			(162)	0
Other liabilities			(22,713)	(1,712)
Net cash flows provided by (used in) operating activities			(33,612)	172,969
Cash flows used in investing activities:
Purchases of property and equipment			(104,384)	(52,289)
Acquisition of the MGE Niagara Resorts, net of cash acquired			(1,666)	(72,287)
Proceeds from notes receivable related to the Cowlitz Project			0	32,026
Investment in Mohegan Hotel Holding, LLC			(10,750)	0	$ (5,000)
Other, net			(1,171)	(12,698)
Net cash flows used in investing activities			(117,971)	(105,248)
Cash flows provided by financing activities:
Other borrowings			2,845	11,335
Other repayments			(14,230)	(6,938)
Payments on finance lease obligations			(1,034)	0
Distributions			(32,333)	(39,000)
Redemption of Mohegan Tribe membership interest in the Cowlitz Project			0	(10,000)
Payments of financing fees			(34)	(3,256)
Other, net			(1,527)	(1,527)
Net cash flows provided by financing activities			84,579	52,181
Net increase (decrease) in cash, cash equivalents, restricted cash and restricted cash equivalents			(67,004)	119,902
Effect of exchange rate on cash, cash equivalents, restricted cash and restricted cash equivalents			(1,444)	(6,155)
Cash, cash equivalents, restricted cash and restricted cash equivalents at beginning of period			280,729	234,626	234,626
Cash, cash equivalents, restricted cash and restricted cash equivalents at end of period	212,281	348,373	212,281	348,373	280,729
Reconciliation of cash, cash equivalents, restricted cash and restricted cash equivalents to the condensed consolidated balance sheets:
Cash and cash equivalents	149,435	162,066	149,435	162,066	130,138
Restricted cash and cash equivalents	1,698	9,321	1,698	9,321	4,960
Restricted cash and cash equivalents	61,148	176,986	61,148	176,986	145,631
Cash, cash equivalents, restricted cash and restricted cash equivalents at end of period	$ 212,281	$ 348,373	212,281	348,373	$ 280,729
Supplemental disclosures:
Cash paid for interest			95,211	101,393
Non-cash transactions:
Right-of-use operating lease assets			360,933
Right-of-use operating lease obligations			361,078
Finance lease assets and obligations			2,511	29,140
Construction payables			46,236	15,739
MGE Niagara Resorts - recognition (derecognition) of build-to-suit asset and liability			(90,675)	77,403
MGE Niagara Resorts – recognition of parking license asset and liability			0	5,222
Payment by third-party for interactive gaming license			0	8,000
Credit Facility | Bank of America, N.A. Revolving and Line of Credit
Cash flows provided by financing activities:
Senior secured credit facility borrowings - revolving and line of credit			807,525	1,014,972
Senior secured credit facility repayments			(662,525)	(966,972)
Credit Facility | Senior Secured Credit Facility, Term Loan A and Term Loan B
Cash flows provided by financing activities:
Senior secured credit facility repayments			(37,104)	(51,011)
Non-cash transactions:
Senior secured credit facility reductions			10,514	13,296
Credit Facility | MGE Niagara Resorts Credit Facility - Revolving
Cash flows provided by financing activities:
Senior secured credit facility borrowings - revolving and line of credit			77,537	0
Senior secured credit facility repayments			(51,110)	0
Credit Facility | MGE Niagara Credit Facility
Cash flows provided by financing activities:
Senior secured credit facility borrowings - revolving and line of credit			0	75,220
Senior secured credit facility repayments			(2,770)	0
Convertible Debenture | MGE Niagara Credit Facility
Cash flows provided by financing activities:
Senior secured credit facility borrowings - revolving and line of credit			0	30,088
Salishan Company, LLC
Cash flows provided by financing activities:
Distributions			$ (661)	$ (730)