Credit Facilities - Narrative (Details)	12 Months Ended
Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)
Line of Credit Facility [Line Items]
Debt annual amortization amount fiscal year 2021	$ 0
Debt annual amortization amount fiscal year 2022	0
Debt annual amortization amount fiscal year 2023	8,250,000
Debt annual amortization fiscal year 2024	38,500,000
Debt annual amortization fiscal year 2025	0
Total repayments of debt	23,250,000	$ 19,000,000
Excess cash flow payment required	0
Interest Rate Swap
Line of Credit Facility [Line Items]
Notional amount of floating-to-fix interest rate swap	$ 22,800,000	28,800,000
Fixed interest rate applicable to swaps	1.61%
Increase in interest expense	$ 400,000
Secured Debt
Line of Credit Facility [Line Items]
Bank term loan	46,750,000	$ 70,000,000
Secured Debt \| Term loan
Line of Credit Facility [Line Items]
Secured term loan, face amount	$ 70,000,000
Fixed charge coverage ratio	1.25
Ratio of debt to EBITDA	2.75
Debt annual amortization amount fiscal year 2021	$ 7,000,000
Debt annual amortization amount fiscal year 2022	7,000,000
Debt annual amortization amount fiscal year 2023	8,750,000
Debt annual amortization fiscal year 2024	8,750,000
Debt annual amortization fiscal year 2025	8,750,000
Voluntary repayments of debt	16,300,000
Total repayments of debt	23,300,000
Bank term loan	$ 46,800,000
Secured Debt \| Term loan \| Maximum
Line of Credit Facility [Line Items]
Ratio of debt to EBITDA	3.75
Debt instrument, interest rate, effective percentage	4.50%
Secured Debt \| Term loan \| Minimum
Line of Credit Facility [Line Items]
Debt instrument, interest rate, effective percentage	2.50%
Secured Debt \| Term loan \| Excess Cash Flow Greater Than or Equal to 2.50
Line of Credit Facility [Line Items]
Percentage of excess cash flow for each year of funded indebtedness to adjusted EBITDA	75.00%
Ratio of funded indebtedness to adjusted EBIDTA	2.50
Secured Debt \| Term loan \| Excess Cash Flow Less Than 2.50 But Greater Than or Equal to 1.50
Line of Credit Facility [Line Items]
Percentage of excess cash flow for each year of funded indebtedness to adjusted EBITDA	50.00%
Secured Debt \| Term loan \| Excess Cash Flow Less Than 2.50 But Greater Than or Equal to 1.50 \| Maximum
Line of Credit Facility [Line Items]
Ratio of funded indebtedness to adjusted EBIDTA	2.50
Secured Debt \| Term loan \| Excess Cash Flow Equal to 1.50
Line of Credit Facility [Line Items]
Ratio of funded indebtedness to adjusted EBIDTA	1.5
Secured Debt \| Term loan \| Excess Cash Flow Less Than 1.50
Line of Credit Facility [Line Items]
Percentage of excess cash flow for each year of funded indebtedness to adjusted EBITDA	0.00%
Ratio of funded indebtedness to adjusted EBIDTA	1.5
Secured Debt \| Secured revolving line of credit
Line of Credit Facility [Line Items]
Line of credit ceiling	$ 25,000,000
Bank term loan	0
Remaining borrowing availability	25,000,000
Secured Debt \| Letters of credit
Line of Credit Facility [Line Items]
Remaining borrowing availability	$ 5,000,000

Debt Instrument, Covenant Compliance, Excess Cash Flow Payment Required

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Fixed Charge Coverage Ratio

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Percentage Of Excess Cash Flow For Each Year Of Funded Indebtedness To Adjusted EBITDA

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Ratio Of Debt To Earnings Before Interest, Taxes, Depreciations, And Amortization

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Voluntary Repayments Of Long-term Debt

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Face (par) amount of debt instrument at time of issuance.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Nominal or face amount used to calculate payments on the derivative asset.

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Fixed interest rate related to the interest rate derivative.

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Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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