SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - ACCUMULATED OTHER COMPREHENSIVE LOSS (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Balance as of beginning of period	$ 1,990,735	$ 1,817,210
Amounts reclassified from accumulated other comprehensive income, net of tax	395	304
Balance as of end of period	2,066,201	1,922,795
Tax on amounts reclassified from accumulated other comprehensive income	(119)	(91)
Total
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Balance as of beginning of period	(9,959)	(4,826)
Balance as of end of period	(9,564)	(4,522)
Cash Flow Hedges
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Balance as of beginning of period	(7,269)	(8,322)
Amounts reclassified from accumulated other comprehensive income, net of tax	264	263
Balance as of end of period	(7,005)	(8,059)
Tax on amounts reclassified from accumulated other comprehensive income	(79)	(79)
Postemployment Benefit Obligation
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Balance as of beginning of period	(2,690)	3,496
Amounts reclassified from accumulated other comprehensive income, net of tax	131	41
Balance as of end of period	(2,559)	3,537
Tax on amounts reclassified from accumulated other comprehensive income	$ (40)	$ (12)