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Shareholders' Equity and Stock-Based Compensation - Additional Information (Detail) - shares | 12 Months Ended |
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2019
Class of Stock [Line Items] |  |  |
Number of shares, options outstanding | 30,000 | 252,492 | 272,492
2009 Plan [Member] |  |  |
Class of Stock [Line Items] |  |  |
Common stock options issued to employees | 0 |  |
Shares available for granting | 0 |  |
Remaining contractual life on the options outstanding | 5 years |  |
Number of options, forfeited or cancelled | 0 |  |
Common Stock [Member] |  |  |
Class of Stock [Line Items] |  |  |
Right of holders to elect company's board of directors | 25.00% |  |
Class B Stock [Member] |  |  |
Class of Stock [Line Items] |  |  |
Right of holders to elect company's board of directors | 75.00% |  |
Class B Stock [Member] | 2009 Plan [Member] | Share-based Compensation Award, Tranche One [Member] |  |  |
Class of Stock [Line Items] |  |  |
Number of shares, options outstanding | 45,000 | 45,000 |
Share based payments, options, expiration date | Sep. 30, 2021 | Sep. 30, 2021 |
Class B Stock [Member] | 2009 Plan [Member] | Share-based Compensation Award, Tranche Two [Member] |  |  |
Class of Stock [Line Items] |  |  |
Number of shares, options outstanding | 30,000 | 30,000 |
Share based payments, options, expiration date | Sep. 26, 2026 | Sep. 26, 2026 |

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- Definition Date the equity-based award expires, in YYYY-MM-DD format. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(3) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition Number of options outstanding, including both vested and non-vested options. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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