Unaudited Condensed Consolidated Statements of Comprehensive Loss - 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 loss	$ (4,976)	$ (121,003)	$ (56,338)	$ (191,434)
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, 2022, respectively, and $(0.1) million and $(0.3) million for the three and six months ended March 31, 2021.	394	457	788	914
Other comprehensive income	394	457	788	914
Comprehensive loss	$ (4,582)	$ (120,546)	$ (55,550)	$ (190,520)