Accounts Receivable - Accounts Receivable, Net (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Receivables [Abstract]
Trade receivables, net	$ 29,750	$ 18,864
Amounts due from manufacturers	11,245	14,343
Other receivables	1,403	796
Accounts receivable, net	$ 42,398	$ 34,003

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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