OTHER COMPREHENSIVE INCOME (LOSS) - Amounts Reclassified from AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total gain (loss)	$ 16,951	$ 13,965
Tax benefit (expense)	(6,339)	(5,212)
Net income	10,612	8,753
Pension and other defined benefit plans | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total gain (loss)	(1,046)	(226)
Cash flow hedges | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total gain (loss)	(56)	682
Accumulated other comprehensive income (loss), attributable to parent | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total gain (loss)	(1,102)	456
Tax benefit (expense)	231	(158)
Net income	$ (871)	$ 298