CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Cash flows provided by operating activities:
Net income (loss)	$ (162,016,000)	$ (2,376,000)	$ 131,608,000
Adjustments to reconcile net income (loss) to net cash flows provided by operating activities:
Depreciation and amortization	109,067,000	122,657,000	81,789,000
Non-cash operating lease expense	12,465,000
Accretion of discounts	1,109,000	1,188,000	2,163,000
Amortization of discounts and debt issuance costs	19,205,000	19,562,000	15,485,000
Provision for (recovery of) losses on receivables	4,592,000	976,000	(5,937,000)
Impairment of Mohegan Sun Pocono's intangible assets	126,596,000	0	0
Impairment of Mohegan Sun Pocono's goodwill	0	39,459,000	0
Deferred income taxes	(7,049,000)	637,000	0
Other, net	1,585,000	(888,000)	609,000
Changes in operating assets and liabilities, net of effect of the MGE Niagara Resorts acquisition:
Accounts receivable	4,423,000	(6,558,000)	(4,859,000)
Accrued interest on notes receivable related to the Cowlitz Project	0	71,579,000	(12,857,000)
Inventories	1,435,000	461,000	(405,000)
Due from Ontario Lottery and Gaming Corporation	7,571,000	(10,943,000)	0
Casino Operating and Services Agreement customer contract asset	(77,026,000)	(53,191,000)	0
Other assets	7,797,000	(3,646,000)	(5,050,000)
Trade payables	5,125,000	1,992,000	725,000
Accrued interest	6,550,000	387,000	391,000
Due to Ontario Lottery and Gaming Corporation	(1,983,000)	29,122,000	0
Operating lease liabilities	3,105,000
Other liabilities	(14,339,000)	(10,019,000)	11,048,000
Net cash flows provided by operating activities	48,212,000	200,399,000	214,710,000
Cash flows used in investing activities:
Purchases of property and equipment	(149,031,000)	(77,613,000)	(136,551,000)
Acquisition of the MGE Niagara Resorts, net of cash acquired	(1,666,000)	(72,287,000)	0
Proceeds from notes receivable related to the Cowlitz Project	0	32,026,000	0
Other, net	(3,929,000)	(7,105,000)	(8,265,000)
Net cash flows used in investing activities	(173,356,000)	(143,580,000)	(144,816,000)
Cash flows provided by (used in) financing activities:
Payments on redemption note payable	(20,434,000)	(3,969,000)	0
Other borrowings	2,845,000	11,335,000	42,264,000
Other repayments	(4,690,000)	(5,450,000)	(269,000)
Payments on finance lease obligations	(1,298,000)	(292,000)	0
Redemption of membership interest related to Project Inspire	0	0	(106,702,000)
Payments of financing fees	(13,752,000)	(3,263,000)	(10,996,000)
Other, net	(1,527,000)	(1,527,000)	(1,527,000)
Net cash flows provided by (used in) financing activities	(14,424,000)	2,041,000	(83,990,000)
Net increase (decrease) in cash, cash equivalents, restricted cash and restricted cash equivalents	(139,568,000)	58,860,000	(14,096,000)
Effect of exchange rate on cash, cash equivalents, restricted cash and restricted cash equivalents	908,000	(12,757,000)	9,666,000
Cash, cash equivalents, restricted cash and restricted cash equivalents at beginning of year	280,729,000	234,626,000	239,056,000
Cash, cash equivalents, restricted cash and restricted cash equivalents at end of year	142,069,000	280,729,000	234,626,000
Reconciliation of cash, cash equivalents, restricted cash and restricted cash equivalents to the consolidated consolidated balance sheets:
Cash, cash equivalents, restricted cash and restricted cash equivalents	280,729,000	234,626,000	234,626,000
Supplemental disclosures:
Cash paid for interest	114,873,000	123,731,000	111,172,000
Non-cash transactions:
Right-of-use operating lease assets	426,403,000	0	0
Right-of-use operating lease obligations	426,548,000	0	0
Finance lease assets and obligations	2,879,000	29,986,000	0
Construction payables	38,172,000	11,888,000	10,747,000
Senior secured credit facility reductions	10,514,000	13,295,000	18,858,000
MGE Niagara Resorts - recognition (derecognition) of build-to-suit asset and liability	(90,675,000)	90,292,000	0
MGE Niagara Resorts - recognition of parking license asset and liability	0	5,242,000	0
Payment by third-party for interactive gaming and sports wagering licenses	0	18,000,000	0
Conversion of redemption liability to redemption note payable	0	0	74,084,000
Ownership rights settlement related to Project Inspire	0	0	6,335,000
Senior Secured Credit Facility, Term Loan A and Term Loan B
Cash flows provided by (used in) financing activities:
Repayments of line of credit	0	0	0
MGE Niagara Credit Facility
Cash flows provided by (used in) financing activities:
Proceeds from line of credit	80,247,000	0	0
Repayments of line of credit	(53,820,000)	0	0
Credit Facility | Senior Secured Credit Facility
Cash flows provided by (used in) financing activities:
Proceeds from line of credit	650,525,000	1,258,939,000	1,382,631,000
Repayments of line of credit	(555,525,000)	(1,222,939,000)	(1,316,631,000)
Credit Facility | Senior Secured Credit Facility - Term Loan B
Cash flows provided by (used in) financing activities:
Proceeds from line of credit	0	0	79,800,000
Credit Facility | Senior Secured Credit Facility, Term Loan A and Term Loan B
Cash flows provided by (used in) financing activities:
Repayments of line of credit	(47,618,000)	(64,307,000)	(86,064,000)
Term Loan | MGE Niagara Credit Facility
Cash flows provided by (used in) financing activities:
Proceeds from line of credit	0	75,220,000	0
Repayments of line of credit	(3,716,000)	(944,000)	0
Convertible Debenture
Cash flows provided by (used in) financing activities:
Proceeds from line of credit	0	30,088,000	0
Mohegan Hotel Holding, LLC
Cash flows used in investing activities:
Investments	(10,750,000)	0	0
Mohegan Tribe
Cash flows provided by (used in) financing activities:
Proceeds from Mohegan Tribe subordinated loan	5,000,000	0	0
Contribution	10,000,000	0	0
Payments of distributions to affiliates	(60,000,000)	(60,000,000)	(60,000,000)
Redemption of Mohegan Tribe membership interest related to the Cowlitz Project	0	(10,000,000)	0
Cowlitz
Cash flows provided by (used in) financing activities:
Payments of distributions to affiliates	0	(730,000)	(6,496,000)
Salishan Company, LLC
Cash flows provided by (used in) financing activities:
Payments of distributions to affiliates	(661,000)	(120,000)	0
Project Inspire
Cash flows used in investing activities:
Investments	$ (7,980,000)	$ (18,601,000)	$ 0