Earnings per Share - Basic and Diluted Earnings 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
Basic earnings per common share:
Net income - basic	$ 14,887	$ 5,330	$ 30,608	$ 9,629
Weighted shares outstanding - basic (in shares)	56,561	55,661	56,370	55,509
Basic earnings per common share (in dollars per share)	$ 0.26	$ 0.10	$ 0.54	$ 0.17
Diluted earnings per common share:
Net income - basic	$ 14,887	$ 5,330	$ 30,608	$ 9,629
Add: Convertible Notes interest expense, net of tax	1,846	0	3,730	0
Net income - diluted	$ 16,733	$ 5,330	$ 34,338	$ 9,629
Weighted shares outstanding - basic (in shares)	56,561	55,661	56,370	55,509
Effect of dilution from equity-based compensation awards (in shares)	622	4	676	2
Effect of dilution from if-converted Convertible Notes (in shares)	25,224	0	25,224	0
Weighted shares outstanding - diluted (in shares)	82,407	55,665	82,270	55,511
Diluted earnings per common share (in dollars per share)	$ 0.20	$ 0.10	$ 0.42	$ 0.17
Potential common shares excluded from the calculation of diluted earnings per share above, Restricted stock (in shares)	1,756	964	1,847	831