Loans and Allowance for Credit Losses on Loans - Transactions In The Allowance For Loan Losses ("ALL") (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Balance	$ 3,451,000	$ 3,319,000	$ 3,390,000	$ 3,581,000
(Release) provision for credit losses on loans	20,000	30,000	80,000	65,000
Charge-offs	(27,000)		(27,000)	(4,000)
Recoveries	1,000		2,000	2,000
Balance	3,445,000	3,349,000	3,445,000	3,349,000
ASU 2016-13 [Member] | Impact of adopting ASC 326 [Member]
Balance				(295,000)
CRE [Member]
Balance	745,000	806,000	830,000	942,000
(Release) provision for credit losses on loans	(25,000)	(18,000)	(110,000)
Balance	720,000	788,000	720,000	788,000
CRE [Member] | ASU 2016-13 [Member] | Impact of adopting ASC 326 [Member]
Balance				(154,000)
MF [Member]
Balance	107,000	49,000	76,000	54,000
(Release) provision for credit losses on loans	(47,000)	22,000	(16,000)	16,000
Balance	60,000	71,000	60,000	71,000
MF [Member] | ASU 2016-13 [Member] | Impact of adopting ASC 326 [Member]
Balance				1,000
C+I [Member]
Balance	234,000	277,000	236,000	184,000
(Release) provision for credit losses on loans	3,000	11,000	1,000	15,000
Balance	237,000	288,000	237,000	288,000
C+I [Member] | ASU 2016-13 [Member] | Impact of adopting ASC 326 [Member]
Balance				89,000
ADL [Member]
Balance	70,000	70,000	105,000	138,000
(Release) provision for credit losses on loans	8,000	31,000	(27,000)	(19,000)
Balance	78,000	101,000	78,000	101,000
ADL [Member] | ASU 2016-13 [Member] | Impact of adopting ASC 326 [Member]
Balance				(18,000)
RES [Member]
Balance	1,608,000	1,910,000	1,601,000	2,048,000
(Release) provision for credit losses on loans	44,000	(174,000)	51,000	(110,000)
Balance	1,652,000	1,736,000	1,652,000	1,736,000
RES [Member] | ASU 2016-13 [Member] | Impact of adopting ASC 326 [Member]
Balance				(202,000)
HELOC [Member]
Balance	171,000	85,000	156,000	81,000
(Release) provision for credit losses on loans	3,000	76,000	18,000	73,000
Balance	174,000	161,000	174,000	161,000
HELOC [Member] | ASU 2016-13 [Member] | Impact of adopting ASC 326 [Member]
Balance				7,000
CON [Member]
Balance	442,000	109,000	357,000	100,000
(Release) provision for credit losses on loans	61,000	95,000	145,000	92,000
Charge-offs	(27,000)		(27,000)	(4,000)
Recoveries	1,000		2,000	2,000
Balance	477,000	204,000	477,000	204,000
CON [Member] | ASU 2016-13 [Member] | Impact of adopting ASC 326 [Member]
Balance				14,000
Unallocated [Member]
Balance	74,000	13,000	29,000	34,000
(Release) provision for credit losses on loans	(27,000)	(13,000)	18,000	(2,000)
Balance	$ 47,000	$ 0	$ 47,000	0
Unallocated [Member] | ASU 2016-13 [Member] | Impact of adopting ASC 326 [Member]
Balance				$ (32,000)