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Loans and Allowance for Credit Losses on Loans - Schedule of Accounts, Notes, Loans and Financing Receivable (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023
Total loans	$ 439,497		$ 438,967
Less allowance for credit losses on loans	(3,517)	$ (3,517)	(3,486)	$ (3,451)	$ (3,420)	$ (3,390)
Net loans	435,980		435,481
CRE [Member]
Total loans	85,955		86,020
Less allowance for credit losses on loans	(654)	(733)	(710)	(745)	(745)	(830)
MF [Member]
Total loans	5,573		5,752
Less allowance for credit losses on loans	(57)	(58)	(59)	(107)	(75)	(76)
C+I [Member]
Total loans	24,902		23,711
Less allowance for credit losses on loans	(202)	(200)	(233)	(234)	(251)	(236)
ADL [Member]
Total loans	13,075		14,946
Less allowance for credit losses on loans	(92)	(119)	(87)	(70)	(80)	(105)
RES [Member]
Total loans	275,881		275,235
Less allowance for credit losses on loans	(1,560)	(1,646)	(1,612)	(1,608)	(1,600)	(1,601)
HELOC [Member]
Total loans	21,354		20,908
Less allowance for credit losses on loans	(237)	(232)	(214)	(171)	(169)	(156)
CON [Member]
Total loans	12,757		12,395
Less allowance for credit losses on loans	$ (542)	$ (554)	$ (439)	$ (442)	$ (372)	$ (357)

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