Earnings per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net (loss) income	$ (2,570)	$ (5,487)	$ 7,059	$ (45,123)
Earnings per common share
Average common share outstanding (denominator) (in shares)	55,898	55,068	55,639	55,395
(Loss) earnings per common share (in dollars per share)	$ (0.05)	$ (0.10)	$ 0.13	$ (0.81)
Diluted earnings per common share
Average common share outstanding (in shares)	55,898	55,068	55,639	55,395
Dilutive effect of restricted stock and convertible notes (in shares)	0	0	14	0
Diluted average common shares outstanding (denominator) (in shares)	55,898	55,068	55,653	55,395
Diluted (loss) earnings per common share (in dollars per share)	$ (0.05)	$ (0.10)	$ 0.13	$ (0.81)
Potential common shares excluded from the calculation of diluted earnings per share above, Restricted stock (in shares)	1,154	3,042	896	2,677