UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 164,040	$ (4,976)	$ 261,185	$ (56,338)
Other comprehensive income, net of income taxes:
Net change related to employee benefit plans, net of income taxes of $(0.1) million and $(0.2) million for the three and six months ended March 31, 2023, respectively, and $(0.1) million and $(0.2) million for the three and six months ended March 31, 2022, respectively	256	394	512	788
Other comprehensive income	256	394	512	788
Comprehensive income (loss)	$ 164,296	$ (4,582)	$ 261,697	$ (55,550)