INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Income Tax Examination [Line Items]
Valuation allowance increase (decrease)	$ 601	$ 999
Undistributed earnings of foreign subsidiaries	143,058
Deferred tax assets, valuation allowance	10,425	9,824
Potential tax benefits impact on effective tax rate	1,106
Liability for uncertainty in income taxes, current	100	77
Domestic Tax Authority
Income Tax Examination [Line Items]
Operating loss carryforwards	0	0
Tax credit carryforward amount	5,933	5,954
Domestic Tax Authority | Capital Loss Carryforward
Income Tax Examination [Line Items]
Tax credit carryforward amount	10,327	10,500
Non-U.S. Tax Authority
Income Tax Examination [Line Items]
Operating loss carryforwards	8,332	9,671
State and Local Jurisdiction
Income Tax Examination [Line Items]
Operating loss carryforwards	$ 139,894	$ 124,191