Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating Loss Carryforwards [Line Items]
Liability for uncertain tax positions, excluding any related interest and penalties	$ 22	$ 22
Liability for uncertain tax position, would impact the effective tax rate, if recognized	22
Accrued interest	15
Interest and penalties from continuing operations	1
Undistributed earnings of foreign subsidiaries	500
Revenue commissioners, Ireland | Subsidiaries
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	5,585
Foreign tax authority
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	1,724
Domestic tax authority
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	14,588
Tax credit carryforward amount subject to expiration	9,107
Tax credit carryforward amount not subject to expiration	5,481
Domestic tax authority | General Business Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	1,337
State tax authority
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	178
State and local jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	$ 21,763