CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 81,045	$ 75,752
Other comprehensive income, net of tax
Reclassifications of losses to net income on derivatives designated as hedging instruments, net of tax of $(112) and $0, respectively	231	0
Adjustment to postemployment benefit obligation, net of tax of $(245) and $(217), respectively	812	759
Other comprehensive income	1,043	759
Comprehensive income	$ 82,088	$ 76,511