Income Taxes - Schedule of Reconciliation of Uncertain Tax Positions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Beginning Balance	$ 1,679	$ 1,175
Additions based on tax positions for the current period	156	563
Reductions for tax positions due to lapse of statute of limitations	(87)
Reductions for tax positions of prior periods	(98)	(59)
Ending Balance	$ 1,650	$ 1,679