Allowance for Credit Losses - Schedule of Allowance Allocated by Portfolio Segment (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Jun. 30, 2025	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
Impaired Loans
Allowance on loans and leases individually evaluated for impairment	$ 3,346		$ 2,692
Allowance on loans and leases collectively evaluated for impairment	18,448		15,746
Total allowance for credit losses	21,794	$ 20,851	18,438	$ 21,965	$ 21,703	$ 22,107
Carrying value of loans and leases individually evaluated for impairment	52,066		42,934
Carrying value of loans and leases collectively evaluated for impairment	2,092,741		1,968,857
Total carrying value of loans and leases	2,144,807		2,011,791
Commercial mortgage
Impaired Loans
Allowance on loans and leases individually evaluated for impairment	292		0
Allowance on loans and leases collectively evaluated for impairment	3,504		3,469
Total allowance for credit losses	3,796	3,411	3,469	3,643	3,676	4,375
Carrying value of loans and leases individually evaluated for impairment	1,241		809
Carrying value of loans and leases collectively evaluated for impairment	871,256		823,167
Total carrying value of loans and leases	872,497		823,976
Home equity lines and loans
Impaired Loans
Allowance on loans and leases individually evaluated for impairment	0		0
Allowance on loans and leases collectively evaluated for impairment	1,341		1,147
Total allowance for credit losses	1,341	1,264	1,147	1,105	1,114	998
Carrying value of loans and leases individually evaluated for impairment	1,583		1,716
Carrying value of loans and leases collectively evaluated for impairment	103,526		89,005
Total carrying value of loans and leases	105,109		90,721
Residential mortgage
Impaired Loans
Allowance on loans and leases individually evaluated for impairment	125		29
Allowance on loans and leases collectively evaluated for impairment	1,180		992
Total allowance for credit losses	1,305	1,097	1,021	981	1,059	1,020
Carrying value of loans and leases individually evaluated for impairment	9,840		7,560
Carrying value of loans and leases collectively evaluated for impairment	236,201		230,504
Total carrying value of loans and leases	246,041		238,064
Construction
Impaired Loans
Allowance on loans and leases individually evaluated for impairment	0		0
Allowance on loans and leases collectively evaluated for impairment	1,805		923
Total allowance for credit losses	1,805	1,581	923	579	591	485
Carrying value of loans and leases individually evaluated for impairment	10,308		8,613
Carrying value of loans and leases collectively evaluated for impairment	304,787		250,940
Total carrying value of loans and leases	315,095		259,553
Commercial and industrial
Impaired Loans
Allowance on loans and leases individually evaluated for impairment	818		855
Allowance on loans and leases collectively evaluated for impairment	3,018		2,243
Total allowance for credit losses	3,836	3,653	3,098	5,879	4,811	4,518
Carrying value of loans and leases individually evaluated for impairment	7,838		11,966
Carrying value of loans and leases collectively evaluated for impairment	410,231		355,400
Total carrying value of loans and leases	418,069		367,366
Small business loans
Impaired Loans
Allowance on loans and leases individually evaluated for impairment	2,111		1,808
Allowance on loans and leases collectively evaluated for impairment	6,195		4,496
Total allowance for credit losses	8,306	7,837	6,304	7,167	7,498	7,005
Carrying value of loans and leases individually evaluated for impairment	21,256		12,270
Carrying value of loans and leases collectively evaluated for impairment	116,638		143,505
Total carrying value of loans and leases	137,894		155,775
Consumer
Impaired Loans
Allowance on loans and leases individually evaluated for impairment	0		0
Allowance on loans and leases collectively evaluated for impairment	0		0
Total allowance for credit losses	0	0	0	0	0	0
Carrying value of loans and leases individually evaluated for impairment	0		0
Carrying value of loans and leases collectively evaluated for impairment	336		349
Total carrying value of loans and leases	336		349
Leases, net
Impaired Loans
Allowance on loans and leases individually evaluated for impairment	0		0
Allowance on loans and leases collectively evaluated for impairment	1,405		2,476
Total allowance for credit losses	1,405	$ 2,008	2,476	$ 2,611	$ 2,954	$ 3,706
Carrying value of loans and leases individually evaluated for impairment	0		0
Carrying value of loans and leases collectively evaluated for impairment	49,766		75,987
Total carrying value of loans and leases	$ 49,766		$ 75,987

Meridian Corp 10-Q