Postretirement Benefits - Pension Amounts Recorded Within Account Line Items of Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Accrued compensation and benefits	$ 419	$ 366
Long-term pension liability	5,932	4,975
Pension and Other Postretirement Defined Benefit Plans, Liabilities	$ 6,351	$ 5,341

Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as noncurrent.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Name:	us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant