ORGANIZATION AND BASIS OF PRESENTATION - Schedule of Estimated Fair Value of Financing Facilities and Notes (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Carrying Value | Fair Value, Inputs, Level 2 | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	$ 2,060,882
Carrying Value | Fair Value, Inputs, Level 2 | Revolving Credit Facility | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	247,000
Carrying Value | Fair Value, Inputs, Level 2 | Term Loan A Facility | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	220,416
Carrying Value | Fair Value, Inputs, Level 2 | Term Loan B Facility | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	792,220
Carrying Value | Fair Value, Inputs, Level 2 | Main Street Term Loan Facility | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	48,127
Carrying Value | Fair Value, Inputs, Level 2 | 2016 7 7/8% Senior Unsecured Notes | Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Note value	492,252
Carrying Value | Fair Value, Inputs, Level 2 | MGE Niagara Credit Facility - Revolving | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	27,464
Carrying Value | Fair Value, Inputs, Level 2 | MGE Niagara Credit Facility - Term Loan | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	71,721
Carrying Value | Fair Value, Inputs, Level 3 | MGE Niagara Resorts Convertible Debenture | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	31,388
Carrying Value | Fair Value, Inputs, Level 3 | Mohegan Expo Credit Facility | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	27,240
Carrying Value | Fair Value, Inputs, Level 3 | Guaranteed Credit Facility | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	28,950
Carrying Value | Fair Value, Inputs, Level 3 | Mohegan Tribe Subordinated Loan | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	5,000
Carrying Value | Fair Value, Inputs, Level 3 | Redemption Note Payable | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	65,289
Carrying Value | Fair Value, Inputs, Level 3 | Other | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	3,815
Fair Value | Fair Value, Inputs, Level 2 | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	2,048,703
Fair Value | Fair Value, Inputs, Level 2 | Revolving Credit Facility | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	237,120
Fair Value | Fair Value, Inputs, Level 2 | Term Loan A Facility | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	217,696
Fair Value | Fair Value, Inputs, Level 2 | Term Loan B Facility | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	773,937
Fair Value | Fair Value, Inputs, Level 2 | Main Street Term Loan Facility | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	50,000
Fair Value | Fair Value, Inputs, Level 2 | 2016 7 7/8% Senior Unsecured Notes | Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Note value	506,875
Fair Value | Fair Value, Inputs, Level 2 | MGE Niagara Credit Facility - Revolving | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	27,464
Fair Value | Fair Value, Inputs, Level 2 | MGE Niagara Credit Facility - Term Loan | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	72,585
Fair Value | Fair Value, Inputs, Level 3 | MGE Niagara Resorts Convertible Debenture | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	31,388
Fair Value | Fair Value, Inputs, Level 3 | Mohegan Expo Credit Facility | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	27,784
Fair Value | Fair Value, Inputs, Level 3 | Guaranteed Credit Facility | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	29,750
Fair Value | Fair Value, Inputs, Level 3 | Mohegan Tribe Subordinated Loan | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	5,000
Fair Value | Fair Value, Inputs, Level 3 | Redemption Note Payable | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	65,289
Fair Value | Fair Value, Inputs, Level 3 | Other | Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	$ 3,815