Summary of Significant Accounting Policies - Carrying Amount of Goodwill and Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020
Goodwill
Balance at beginning of year	$ 13,801	$ 13,801
Balance at end of year	13,801	13,801
Intangible assets
Balance at beginning of year	791	1,066
Amortization	(271)	(275)
Balance at end of year	$ 520	$ 791

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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