Summary of Significant Accounting Policies - Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net income (loss)	$ 2,993	$ (1,342)
Weighted-average common shares outstanding (basic and diluted) (in shares)	5,691,000	5,612,000
Effect of dilutive securities:
Weighted-average common shares outstanding (basic and diluted) (in shares)	5,890,000	5,612,000
Net loss per share – basic:
Net income (loss) per share – basic (in dollars per share)	$ 0.53	$ (0.24)
Net income (loss) per share – diluted (in dollars per share)	$ 0.51	$ (0.24)
Anti-dilutive weighted-average common shares excluded from calculation of diluted earnings per share (in shares)	219,000	194,000
Restricted shares
Effect of dilutive securities:
Restricted and performance shares (in shares)	161,000	0
Net loss per share – basic:
Anti-dilutive weighted-average common shares excluded from calculation of diluted earnings per share (in shares)		0
Performance shares
Effect of dilutive securities:
Restricted and performance shares (in shares)	38,000	0