Stock Award Plans - Other Stock Option Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Share-based Payment Arrangement [Abstract]
Compensation cost for stock options	$ 1,344	$ 521	$ 0
Weighted average grant date fair value per stock option (in dollars per share)	$ 4.37	$ 5.21	$ 3.15
Total intrinsic value of options exercised	$ 102	$ 414	$ 908
Grant date fair value of options exercised	33	51	285
Cash received from option exercises	$ 144	$ 298	$ 1,338

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of cash inflow from exercise of option under share-based payment arrangement.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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