BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Promotional Allowances (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Schedule of Promotional Allowances [Line Items]
Retail value of providing promotional allowances	$ 105,347	$ 96,593	$ 97,346
Cost of providing promotional allowances	85,872	76,650	79,079
Reductions to gaming revenues related to discounts provided on patron losses	11,900	15,900	9,700
Reductions to gaming revenues related to player club points redeemed for cash	1,300	1,500	1,400
Food and beverage
Schedule of Promotional Allowances [Line Items]
Retail value of providing promotional allowances	40,657	41,800	42,192
Cost of providing promotional allowances	31,680	33,536	35,122
Hotel
Schedule of Promotional Allowances [Line Items]
Retail value of providing promotional allowances	17,873	15,364	15,142
Cost of providing promotional allowances	10,790	8,615	8,398
Retail, entertainment and other
Schedule of Promotional Allowances [Line Items]
Retail value of providing promotional allowances	46,817	39,429	40,012
Cost of providing promotional allowances	$ 43,402	$ 34,499	$ 35,559