Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Taxes Disclosure [Line Items]
Deferred tax assets operating loss and tax credit carryforwards	$ 10,164	$ 494
Deferred tax assets	17,405	4,213
Unrecognized income tax benefits	568	509	$ 388
Amount of unrecognized tax benefits which would favorably affect the effective tax rate if recognized	494
Penalties and interest	20	34
Accrued for the payment of interest and penalties	$ 138	118
Uncertain tax positions expected to be paid or settled	12 months
Cash paid for income taxes	$ 9,816	7,840	6,555
GILTI inclusion	23,666	5,328
Tax expense	4,970	1,119
Foreign tax credit benefit	4,767	990	$ 15
Deferred tax liability	185
Amended Return [Member]
Income Taxes Disclosure [Line Items]
Tax liability reduction from final tax regulations		220
Domestic [Member]
Income Taxes Disclosure [Line Items]
Deferred tax assets operating loss and tax credit carryforwards	$ 205	231
Operating loss carryforwards, expiration period start year	2023
Aggregate amount of federal, state and foreign operating loss carryforwards	$ 243
Open Tax Years	fiscal 2016 remain open
Foreign [Member]
Income Taxes Disclosure [Line Items]
Deferred tax assets operating loss and tax credit carryforwards	$ 9,959	263
Aggregate amount of federal, state and foreign operating loss carryforwards	$ 78,332
Open Tax Years	2015 and forward
State [Member]
Income Taxes Disclosure [Line Items]
Operating loss carryforwards, expiration period end year	2036
Aggregate amount of federal, state and foreign operating loss carryforwards	$ 2,432
Global Intangible Low Taxed Income [Member]
Income Taxes Disclosure [Line Items]
Foreign tax credit benefit	$ 4,767	$ 990