CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 96,035	$ 149,809	$ 207,347	$ 230,854
Other comprehensive income, net of tax
Reclassifications of losses to net income on derivatives designated as hedging instruments, net of tax of $(80), $(79), $(159) and $(191), respectively	263	263	527	494
Adjustment to postemployment benefit obligation, net of tax of $(232), $(244), $(465) and $(489), respectively	768	813	1,534	1,625
Other comprehensive income	1,031	1,076	2,061	2,119
Comprehensive income	$ 97,066	$ 150,885	$ 209,408	$ 232,973