Summary of Significant Accounting Policies - Net Income (Loss) per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net (loss) income	$ (3,691)	$ 2,993
Weighted-average common shares outstanding (basic) (in shares)	5,800	5,691
Effect of dilutive securities:
Weighted-average common shares outstanding (diluted) (in shares)	5,800	5,890
Net income per share
Net income per share – basic (in dollars per share)	$ (0.64)	$ 0.53
Net income per share – diluted (in dollars per share)	$ (0.64)	$ 0.51
Anti-dilutive weighted-average common shares excluded from calculation of diluted earnings per share (in shares)	297	219
Restricted shares
Effect of dilutive securities:
Restricted and performance shares (in shares)	0	161
Performance shares
Effect of dilutive securities:
Restricted and performance shares (in shares)	0	38