Supporting Financial Information - Debt Obligations (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Sep. 30, 2019
Debt Instrument [Line Items]
Long-term portion of bank debt obligation	$ 42,542	$ 53,629
Secured Debt
Debt Instrument [Line Items]
Bank term loan	44,500	56,000
Less unamortized deferred financing cost	(1,958)	(2,371)
Net bank debt obligation	42,542	53,629
Less current portion of term loan debt obligations	0	0
Long-term portion of bank debt obligation	$ 42,542	$ 53,629

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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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Subparagraph (b)(3)
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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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