Securities Sold Under Agreement to Repurchase and Other Borrowings - Additional Information (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Securities sold under agreement to repurchase, Amount	$ 224,000	$ 197,000
U.S. Agency Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Securities sold under agreement to repurchase, Amount	$ 977,000	$ 4,900,000

Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant