Income Taxes - Unrecognized tax benefits (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Balance, beginning of year	$ 0	$ 220
Additions for tax positions of current year	78
Additions for tax positions of prior years	265
Accrued penalties and interest		13
Reversal for statute of limitations		(233)
Balance, end of period	$ 343	$ 0

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Amount of unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 10B
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- Definition

Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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- Definition

Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

+ References

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

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-Name Accounting Standards Codification
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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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