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Federal Funds Purchased and Securities Sold Under Agreement to Repurchase - Daily Securities Sold under Agreement to Repurchase (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amount Outstanding at End of Period	$ 30,200
Daily Securities Sold Under Agreement to Repurchase [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amount Outstanding at End of Period	$ 1,814	$ 806
Weighted Average Rate End of Period	1.08%	1.04%
Maximum Amount Borrowings Outstanding Month End	$ 1,864	$ 819
Approximate Average Outstanding in Period	$ 1,302	$ 1,026
Approximate Weighted Average Interest Rate For the Period	0.65%	1.12%
Term CDs Sold Under Agreement to Repurchase [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amount Outstanding at End of Period	$ 28,416	$ 24,889
Weighted Average Rate End of Period	1.39%	2.00%
Maximum Amount Borrowings Outstanding Month End	$ 28,416	$ 24,889
Approximate Average Outstanding in Period	$ 26,421	$ 23,793
Approximate Weighted Average Interest Rate For the Period	2.33%	1.87%

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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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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
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