ORGANIZATION AND BASIS OF PRESENTATION - Schedule of Estimated Fair Value of Financing Facilities and Notes (Details) - Fair Value, Inputs, Level 2 $ in Thousands	Dec. 31, 2019 USD ($)
Carrying Value | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	$ 1,960,018
Carrying Value | Revolving Credit Facility | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	137,000
Carrying Value | Term Loan A Facility | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	253,272
Carrying Value | Term Loan B Facility | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	804,174
Carrying Value | 2016 7 7/8% Senior Unsecured Notes | Senior Unsecured Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Note value	490,821
Carrying Value | Line of Credit | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	75
Carrying Value | MGE Niagara Credit Facility - Revolving | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	30,728
Carrying Value | MGE Niagara Credit Facility - Term Loan | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	73,936
Carrying Value | MGE Niagara Convertible Debentures | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	30,728
Carrying Value | Mohegan Expo Credit Facility | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	28,831
Carrying Value | Guaranteed Credit Facility | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	31,264
Carrying Value | Redemption Note Payable | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	78,035
Carrying Value | Other | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	1,154
Fair Value | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	1,965,755
Fair Value | Revolving Credit Facility | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	134,089
Fair Value | Term Loan A Facility | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	252,122
Fair Value | Term Loan B Facility | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	789,393
Fair Value | 2016 7 7/8% Senior Unsecured Notes | Senior Unsecured Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Note value	512,500
Fair Value | Line of Credit | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	74
Fair Value | MGE Niagara Credit Facility - Revolving | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	30,728
Fair Value | MGE Niagara Credit Facility - Term Loan | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	74,900
Fair Value | MGE Niagara Convertible Debentures | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	30,728
Fair Value | Mohegan Expo Credit Facility | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	29,657
Fair Value | Guaranteed Credit Facility | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	32,375
Fair Value | Redemption Note Payable | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	78,035
Fair Value | Other | Line of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit facility value	$ 1,154