Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Taxes Disclosure [Line Items]
Provisional repatriation transition tax	$ 876	$ 854
Tax rate used for re-measurement of temporary differences expected to be realized during fiscal 2018		24.50%
Tax rate used for re-measurement of remaining temporary differences	21.00%
Tax benefit from tax reform act		$ 1,695
Accrued Income Taxes Current [Member]
Income Taxes Disclosure [Line Items]
Provisional repatriation transition tax	$ 140
Accrued Income Taxes Noncurrent [Member]
Income Taxes Disclosure [Line Items]
Provisional repatriation transition tax	$ 736