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

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Stock-Based Compensation - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 0.2	$ 0.1	$ 0.6	$ 0.1
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	0.2	$ 0.1	0.6	$ 0.1
Compensation cost, not yet recognized	$ 0.9		$ 0.9
Recognized over a period			2 years 9 months
The 2015 Incentive Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, capital shares reserved for future issuance (in shares)	2,100,415		2,100,415
Number of shares available for grant (in shares)	450,636		450,636