Loans - Information About Loans And The ALL By Portfolio Segment Are Summarized (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Individually evaluated for impairment	$ 1,312		$ 1,171
Collectively evaluated for impairment	380,209		342,628
Total	381,521		343,799
Collectively evaluated for impairment	3,153		2,875
Total	3,153	$ 3,009	2,875	$ 2,832	$ 2,806	$ 2,806
CRE [Member]
Individually evaluated for impairment	229		109
Collectively evaluated for impairment	68,839		70,085
Total	69,068		70,194
Collectively evaluated for impairment	740		781
Total	740	796	781	722	644	560
MF [Member]
Collectively evaluated for impairment	6,425		4,888
Total	6,425		4,888
Collectively evaluated for impairment	52		23
Total	52	48	23	22	21	22
C+I [Member]
Individually evaluated for impairment	1,018		996
Collectively evaluated for impairment	52,678		23,680
Total	53,696		24,676
Collectively evaluated for impairment	278		350
Total	278	287	350	216	220	232
ADL [Member]
Collectively evaluated for impairment	23,637		18,844
Total	23,637		18,844
Collectively evaluated for impairment	223		145
Total	223	135	145	82	143	88
RES [Member]
Individually evaluated for impairment	65		66
Collectively evaluated for impairment	217,311		213,256
Total	217,376		213,322
Collectively evaluated for impairment	1,690		1,503
Total	1,690	1,643	1,503	1,728	1,585	1,593
HELOC [Member]
Collectively evaluated for impairment	9,359		10,123
Total	9,359		10,123
Collectively evaluated for impairment	58		52
Total	58	79	52	54	51	69
CON [Member]
Collectively evaluated for impairment	1,960		1,752
Total	1,960		1,752
Collectively evaluated for impairment	29		18
Total	29	20	18	9	5	7
Unallocated [Member]
Collectively evaluated for impairment	83		3
Total	$ 83	$ 1	$ 3	$ (1)	$ 137	$ 235