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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Name:	us-gaap_Goodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Business Combinations - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Jan. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Goodwill	$ 26,051		$ 23,857
TransChart LLC
Business Acquisition [Line Items]
Goodwill		$ 2,200
Intangible assets		$ 2,000