INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Tax Credit Carryforward [Line Items]
Net operating loss	$ 162,016	$ 2,376	$ (131,608)
MGE Niagara Resorts
Tax Credit Carryforward [Line Items]
Net operating loss	$ 16,300