ORGANIZATION AND BASIS OF PRESENTATION - Revenue Disaggregation (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Net revenues	$ 399,052	$ 319,500
Connecticut
Disaggregation of Revenue [Line Items]
Net revenues	243,335	252,679
Pennsylvania
Disaggregation of Revenue [Line Items]
Net revenues	61,954	60,791
Niagara Falls
Disaggregation of Revenue [Line Items]
Net revenues	84,974	0
Other
Disaggregation of Revenue [Line Items]
Net revenues	9,120	6,090
Gaming
Disaggregation of Revenue [Line Items]
Net revenues	264,269	221,935
Gaming | Connecticut
Disaggregation of Revenue [Line Items]
Net revenues	160,259	170,482
Gaming | Pennsylvania
Disaggregation of Revenue [Line Items]
Net revenues	51,978	51,453
Gaming | Niagara Falls
Disaggregation of Revenue [Line Items]
Net revenues	52,032	0
Gaming | Other
Disaggregation of Revenue [Line Items]
Net revenues	0	0
Food and beverage
Disaggregation of Revenue [Line Items]
Net revenues	50,532	34,806
Food and beverage | Connecticut
Disaggregation of Revenue [Line Items]
Net revenues	28,533	29,135
Food and beverage | Pennsylvania
Disaggregation of Revenue [Line Items]
Net revenues	6,082	5,713
Food and beverage | Niagara Falls
Disaggregation of Revenue [Line Items]
Net revenues	15,953	0
Food and beverage | Other
Disaggregation of Revenue [Line Items]
Net revenues	(36)	(42)
Hotel
Disaggregation of Revenue [Line Items]
Net revenues	27,589	22,977
Hotel | Connecticut
Disaggregation of Revenue [Line Items]
Net revenues	22,048	21,220
Hotel | Pennsylvania
Disaggregation of Revenue [Line Items]
Net revenues	1,980	1,758
Hotel | Niagara Falls
Disaggregation of Revenue [Line Items]
Net revenues	3,563	0
Hotel | Other
Disaggregation of Revenue [Line Items]
Net revenues	(2)	(1)
Retail, entertainment and other
Disaggregation of Revenue [Line Items]
Net revenues	56,662	39,782
Retail, entertainment and other | Connecticut
Disaggregation of Revenue [Line Items]
Net revenues	32,495	31,842
Retail, entertainment and other | Pennsylvania
Disaggregation of Revenue [Line Items]
Net revenues	1,914	1,867
Retail, entertainment and other | Niagara Falls
Disaggregation of Revenue [Line Items]
Net revenues	13,426	0
Retail, entertainment and other | Other
Disaggregation of Revenue [Line Items]
Net revenues	146	421
Management and development | Connecticut
Disaggregation of Revenue [Line Items]
Net revenues	0	0
Management and development | Pennsylvania
Disaggregation of Revenue [Line Items]
Net revenues	0	0
Management and development | Niagara Falls
Disaggregation of Revenue [Line Items]
Net revenues	0	0
Management and development | Other
Disaggregation of Revenue [Line Items]
Net revenues	$ 9,012	$ 5,712