Loans and Allowance for Credit Losses on Loans - Schedule of Accounts, Notes, Loans and Financing Receivable (Detail) - USD ($) $ in Thousands	Jun. 30, 2026	Mar. 31, 2026	Dec. 31, 2025	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 421,864		$ 419,474
Less allowance for credit losses on loans	(3,428)	$ (3,427)	(3,427)	$ (3,517)	$ (3,517)	$ (3,486)
Net loans	418,436		416,047
CRE [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	75,406		80,588
Less allowance for credit losses on loans	(497)	(532)	(618)	(654)	(733)	(710)
MF [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	4,220		4,839
Less allowance for credit losses on loans	(43)	(49)	(48)	(57)	(58)	(59)
C+I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	26,805		22,541
Less allowance for credit losses on loans	(214)	(170)	(183)	(202)	(200)	(233)
ADL [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	15,806		12,875
Less allowance for credit losses on loans	(119)	(107)	(88)	(92)	(119)	(87)
RES [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	264,362		265,249
Less allowance for credit losses on loans	(1,465)	(1,452)	(1,488)	(1,560)	(1,646)	(1,612)
HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	23,572		20,652
Less allowance for credit losses on loans	(234)	(216)	(204)	(237)	(232)	(214)
CON [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	11,693		12,730
Less allowance for credit losses on loans	$ (545)	$ (667)	$ (609)	$ (542)	$ (554)	$ (439)