Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income (loss)	$ 1,553	$ (2,570)	$ 5,330	$ 4,299	$ (23,340)	$ (5,487)	$ (40,874)	$ 1,238	$ 8,612	$ (68,463)	$ 2,541
Earnings per common share
Average common share outstanding (denominator) (in shares)									55,744	55,313	55,341
Earnings (loss) per common share (in dollars per share)	$ 0.03	$ (0.05)	$ 0.10	$ 0.08	$ (0.42)	$ (0.10)	$ (0.74)	$ 0.02	$ 0.15	$ (1.24)	$ 0.05
Diluted earnings per common share
Average common share outstanding (in shares)									55,744	55,313	55,341
Dilutive effect of restricted stock and convertible notes (in shares)									205	0	643
Diluted average common shares outstanding (denominator) (in shares)									55,949	55,313	55,984
Diluted earnings (loss) per common share (in dollars per share)	$ 0.03	$ (0.05)	$ 0.10	$ 0.08	$ (0.42)	$ (0.10)	$ (0.74)	$ 0.02	$ 0.15	$ (1.24)	$ 0.05
Potential common shares excluded from the calculation of diluted earnings per share above, Restricted stock (in shares)									1,233	2,786	2,121