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, 2022	Dec. 31, 2021
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amount Outstanding at End of Period	$ 31,600
Daily Securities Sold Under Agreement to Repurchase [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amount Outstanding at End of Period	$ 1,115	$ 1,062
Weighted Average Rate End of Period	0.95%	0.70%
Maximum Amount Borrowings Outstanding Month End	$ 1,450	$ 1,991
Approximate Average Outstanding in Period	$ 1,169	$ 1,514
Approximate Weighted Average Interest Rate For the Period	0.43%	0.43%
Term CDs Sold Under Agreement to Repurchase [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amount Outstanding at End of Period	$ 30,518	$ 28,206
Weighted Average Rate End of Period	0.97%	1.00%
Maximum Amount Borrowings Outstanding Month End	$ 34,504	$ 28,362
Approximate Average Outstanding in Period	$ 31,573	$ 28,315
Approximate Weighted Average Interest Rate For the Period	2.54%	2.56%