INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Tax Credit Carryforward [Line Items]
Net operating income	$ 7,353	$ (162,016)	$ (2,376)
MGE Niagara Resorts
Tax Credit Carryforward [Line Items]
Net operating income	41,600
Operating loss carryforwards	$ 98,800