Long-Term Debt - Schedule of Long-term Debt Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Nov. 04, 2021	Sep. 30, 2021
Debt Schedule [Abstract]
Long-term debt, fair value	$ 2,491,685
Less: current portion of long-term debt, fair value	(66,793)
Long-term debt, net of current portion, fair value	2,424,892
Fair value	2,379,096
Long-term debt, book value	2,310,586		$ 1,938,754
Less: current portion of long-term debt, book value	(66,793)		(80,276)
Long-term debt, net of current portion, book value	2,243,793		1,858,478
Unamortized discounts and debt issuance costs	181,099		34,022
MGE Korea Term Loan
Debt Schedule [Abstract]
Stated interest rate		17.00%
Line of Credit | New Senior Secured Credit Facility
Debt Schedule [Abstract]
Long-term debt, fair value	40,000
Long-term debt, book value	40,000		27,000
Line of Credit | Line of Credit
Debt Schedule [Abstract]
Long-term debt, fair value	0
Long-term debt, book value	0		20,227
Line of Credit | MGE Niagara Credit Facility - Revolving
Debt Schedule [Abstract]
Long-term debt, fair value	15,990
Long-term debt, book value	15,990		27,534
Line of Credit | MGE Niagara Credit Facility - Swingline
Debt Schedule [Abstract]
Long-term debt, fair value	12,252
Long-term debt, book value	12,252		4,333
Line of Credit | MGE Niagara Credit Facility - Term Loan
Debt Schedule [Abstract]
Long-term debt, fair value	68,957
Long-term debt, book value	68,253		68,965
Line of Credit | Inspire Korea Credit Facility
Debt Schedule [Abstract]
Long-term debt, fair value	257,367
Long-term debt, book value	199,726		0
Line of Credit | MGE Korea Term Loan
Debt Schedule [Abstract]
Long-term debt, fair value	287,077
Long-term debt, book value	191,718		0
Line of Credit | Mohegan Expo Credit Facility (1)
Debt Schedule [Abstract]
Long-term debt, fair value	24,662
Long-term debt, book value	24,662		25,697
Line of Credit | Guaranteed Credit Facility
Debt Schedule [Abstract]
Long-term debt, fair value	26,468
Long-term debt, book value	$ 26,042		27,208
Senior Notes | 2021 8% Senior Secured Notes
Debt Schedule [Abstract]
Stated interest rate	8.00%
Long-term debt, fair value	$ 1,175,000
Long-term debt, book value	1,159,406		1,157,731
Senior Notes | 2016 7 7/8% Senior Unsecured Notes
Debt Schedule [Abstract]
Long-term debt, fair value	500,000
Long-term debt, book value	494,545		493,599
Convertible Debenture | MGE Niagara Convertible Debenture
Debt Schedule [Abstract]
Long-term debt, fair value	31,980
Long-term debt, book value	31,980		31,468
Redemption Note Payable | Redemption Note Payable
Debt Schedule [Abstract]
Long-term debt, fair value	50,360
Long-term debt, book value	$ 44,440		53,130
Other | 2016 7 7/8% Senior Unsecured Notes
Debt Schedule [Abstract]
Stated interest rate	7.875%
Other | Other
Debt Schedule [Abstract]
Long-term debt, fair value	$ 1,572
Long-term debt, book value	$ 1,572		$ 1,862