UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 95,293	$ 17,752	$ 356,478	$ (38,586)
Other comprehensive income, net of income taxes:
Net change related to employee benefit plans, net of income taxes of $(59.6) thousand and $(209.8) thousand for the three and nine months ended June 30, 2023, respectively, and $(41.7) thousand and $(268.4) thousand for the three and nine months ended June 30, 2022, respectively	255	389	767	1,177
Other comprehensive income	255	389	767	1,177
Comprehensive income (loss)	$ 95,548	$ 18,141	$ 357,245	$ (37,409)