Earnings (Loss) Per Share - Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net income (loss) available to common shares	$ 34,571	$ (149,808)	$ 61,999	$ (118,278)
Denominator:
Weighted average common shares (in shares)	28,609	29,210	28,526	29,164
Weighted average effect of dilutive securities
Weighted average effect of dilutive securities (in shares)	390	0	383	0
Diluted weighted average common shares (in shares)	28,999	29,210	28,909	29,164
Earnings (loss) per share:
Basic (in dollars per share)	$ 1.21	$ (5.13)	$ 2.17	$ (4.06)
Diluted (in dollars per share)	$ 1.19	$ (5.13)	$ 2.14	$ (4.06)