Loans and Allowance for Credit Losses - Loan Balances by Year of Origination and Internally Assigned Risk Rating (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Total Loan Balance
Current fiscal year	$ 893,015	$ 1,117,436
Year two	1,134,650	1,320,936
Year three	1,191,528	1,094,225
Year four	897,782	503,703
Year five	421,743	645,502
More than five years	1,885,462	1,650,211
Revolving	1,284,808	1,292,135
Revolving-Term	33,970	29,193
Total	7,742,958	7,653,341
Year-to-date Gross Charge-offs
Current fiscal year	839	830
Year two	191	214
Year three	288	218
Year four	1,338	25
Year five	91	3,989
More than five years	6,837	18,669
Revolving	1,118	109
Revolving-Term	1,486	584
Total	12,188	24,638
Pass
Total Loan Balance
Current fiscal year	892,431	1,117,247
Year two	1,128,069	1,318,412
Year three	1,171,403	1,060,514
Year four	870,715	499,034
Year five	417,507	595,848
More than five years	1,775,175	1,473,853
Revolving	1,243,868	1,253,528
Revolving-Term	30,962	25,838
Total	7,530,130	7,344,274
Special mention
Total Loan Balance
Current fiscal year	0	189
Year two	2,020	1,681
Year three	17,638	16,493
Year four	2,112	224
Year five	157	24,920
More than five years	65,401	87,973
Revolving	11,322	4,163
Revolving-Term	268	172
Total	98,918	135,815
Substandard
Total Loan Balance
Current fiscal year	584	0
Year two	4,561	843
Year three	2,487	17,218
Year four	24,589	4,445
Year five	3,196	24,734
More than five years	44,886	88,385
Revolving	26,717	34,444
Revolving-Term	2,740	3,183
Total	109,760	173,252
Doubtful
Total Loan Balance
Current fiscal year	0	0
Year two	0	0
Year three	0	0
Year four	366	0
Year five	883	0
More than five years	0	0
Revolving	2,901	0
Revolving-Term	0	0
Total	4,150	0
Commercial Loans | Commercial real estate
Total Loan Balance
Current fiscal year	278,187	276,677
Year two	289,081	324,469
Year three	363,529	439,308
Year four	415,621	240,256
Year five	215,632	419,371
More than five years	1,110,490	926,636
Revolving	35,991	32,418
Revolving-Term	0	0
Total	2,708,531	2,659,135
Year-to-date Gross Charge-offs
Current fiscal year	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
More than five years	5,205	1,706
Revolving	0	0
Revolving-Term	0	0
Total	5,205	1,706
Commercial Loans | Commercial and industrial
Total Loan Balance
Current fiscal year	120,143	171,861
Year two	148,100	231,978
Year three	195,756	210,636
Year four	152,971	54,696
Year five	31,312	52,858
More than five years	197,426	193,905
Revolving	505,929	520,249
Revolving-Term	0	0
Total	1,351,637	1,436,183
Year-to-date Gross Charge-offs
Current fiscal year	0	0
Year two	78	0
Year three	0	0
Year four	1,235	0
Year five	0	3,412
More than five years	91	15,842
Revolving	1,032	0
Revolving-Term	0	0
Total	2,436	19,254
Commercial Loans | Commercial construction
Total Loan Balance
Current fiscal year	119,355	75,596
Year two	121,816	154,456
Year three	73,851	82,313
Year four	14,911	14,845
Year five	884	4,727
More than five years	2,139	4,438
Revolving	8,310	14,208
Revolving-Term	0	0
Total	341,266	350,583
Year-to-date Gross Charge-offs
Current fiscal year	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	451
More than five years	0	0
Revolving	0	0
Revolving-Term	0	0
Total	0	451
Commercial Loans | Business banking
Total Loan Balance
Current fiscal year	149,624	270,129
Year two	233,041	262,606
Year three	226,654	207,611
Year four	177,683	88,018
Year five	76,643	99,574
More than five years	345,327	334,766
Revolving	92,981	96,754
Revolving-Term	1,305	1,307
Total	1,303,258	1,360,765
Year-to-date Gross Charge-offs
Current fiscal year	0	0
Year two	79	67
Year three	124	43
Year four	0	1
Year five	56	88
More than five years	1,486	1,073
Revolving	0	34
Revolving-Term	0	0
Total	1,745	1,306
Commercial Loans | Pass | Commercial real estate
Total Loan Balance
Current fiscal year	278,187	276,677
Year two	287,081	323,463
Year three	362,174	433,308
Year four	413,781	237,901
Year five	213,384	383,799
More than five years	1,040,703	781,465
Revolving	35,737	32,418
Revolving-Term	0	0
Total	2,631,047	2,469,031
Commercial Loans | Pass | Commercial and industrial
Total Loan Balance
Current fiscal year	119,580	171,672
Year two	147,007	231,114
Year three	194,363	185,884
Year four	131,877	53,101
Year five	30,093	47,063
More than five years	175,359	183,165
Revolving	466,640	482,490
Revolving-Term	0	0
Total	1,264,919	1,354,489
Commercial Loans | Pass | Commercial construction
Total Loan Balance
Current fiscal year	119,355	75,596
Year two	121,816	154,456
Year three	57,853	82,313
Year four	14,911	14,845
Year five	884	151
More than five years	2,139	4,054
Revolving	8,310	14,208
Revolving-Term	0	0
Total	325,268	345,623
Commercial Loans | Pass | Business banking
Total Loan Balance
Current fiscal year	149,603	270,129
Year two	230,784	262,535
Year three	225,318	204,874
Year four	173,763	87,346
Year five	76,087	96,371
More than five years	332,707	321,360
Revolving	92,756	96,618
Revolving-Term	597	523
Total	1,281,615	1,339,756
Commercial Loans | Special mention | Commercial real estate
Total Loan Balance
Current fiscal year	0	0
Year two	2,000	1,006
Year three	370	6,000
Year four	1,840	0
Year five	0	24,887
More than five years	46,104	75,428
Revolving	254	0
Revolving-Term	0	0
Total	50,568	107,321
Commercial Loans | Special mention | Commercial and industrial
Total Loan Balance
Current fiscal year	0	189
Year two	20	620
Year three	1,221	10,242
Year four	142	0
Year five	10	0
More than five years	14,896	8,848
Revolving	11,033	4,126
Revolving-Term	0	0
Total	27,322	24,025
Commercial Loans | Special mention | Commercial construction
Total Loan Balance
Current fiscal year	0	0
Year two	0	0
Year three	15,998	0
Year four	0	0
Year five	0	0
More than five years	0	0
Revolving	0	0
Revolving-Term	0	0
Total	15,998	0
Commercial Loans | Special mention | Business banking
Total Loan Balance
Current fiscal year	0	0
Year two	0	55
Year three	49	251
Year four	130	224
Year five	147	33
More than five years	4,302	3,508
Revolving	35	37
Revolving-Term	268	172
Total	4,931	4,280
Commercial Loans | Substandard | Commercial real estate
Total Loan Balance
Current fiscal year	0	0
Year two	0	0
Year three	985	0
Year four	0	2,355
Year five	1,834	10,685
More than five years	23,683	69,743
Revolving	0	0
Revolving-Term	0	0
Total	26,502	82,783
Commercial Loans | Substandard | Commercial and industrial
Total Loan Balance
Current fiscal year	563	0
Year two	1,073	244
Year three	172	14,510
Year four	20,586	1,595
Year five	740	5,795
More than five years	7,171	1,892
Revolving	25,355	33,633
Revolving-Term	0	0
Total	55,660	57,669
Commercial Loans | Substandard | Commercial construction
Total Loan Balance
Current fiscal year	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	4,576
More than five years	0	384
Revolving	0	0
Revolving-Term	0	0
Total	0	4,960
Commercial Loans | Substandard | Business banking
Total Loan Balance
Current fiscal year	21	0
Year two	2,257	16
Year three	1,287	2,486
Year four	3,790	448
Year five	409	3,170
More than five years	8,318	9,898
Revolving	190	99
Revolving-Term	440	612
Total	16,712	16,729
Commercial Loans | Doubtful | Commercial real estate
Total Loan Balance
Current fiscal year	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	414	0
More than five years	0	0
Revolving	0	0
Revolving-Term	0	0
Total	414	0
Commercial Loans | Doubtful | Commercial and industrial
Total Loan Balance
Current fiscal year	0	0
Year two	0	0
Year three	0	0
Year four	366	0
Year five	469	0
More than five years	0	0
Revolving	2,901	0
Revolving-Term	0	0
Total	3,736	0
Commercial Loans | Doubtful | Commercial construction
Total Loan Balance
Current fiscal year	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
More than five years	0	0
Revolving	0	0
Revolving-Term	0	0
Total	0	0
Commercial Loans | Doubtful | Business banking
Total Loan Balance
Current fiscal year	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
More than five years	0	0
Revolving	0	0
Revolving-Term	0	0
Total	0	0
Consumer Loans | Consumer real estate
Total Loan Balance
Current fiscal year	217,250	311,887
Year two	335,763	335,462
Year three	324,389	147,850
Year four	133,347	102,041
Year five	95,504	67,890
More than five years	229,462	189,794
Revolving	570,558	552,080
Revolving-Term	27,236	24,774
Total	1,933,509	1,731,778
Year-to-date Gross Charge-offs
Current fiscal year	0	0
Year two	0	1
Year three	0	0
Year four	0	5
Year five	9	1
More than five years	37	43
Revolving	86	75
Revolving-Term	1,216	296
Total	1,348	421
Consumer Loans | Other consumer
Total Loan Balance
Current fiscal year	8,456	11,286
Year two	6,849	11,965
Year three	7,349	6,507
Year four	3,249	3,847
Year five	1,768	1,082
More than five years	618	672
Revolving	71,039	76,426
Revolving-Term	5,429	3,112
Total	104,757	114,897
Year-to-date Gross Charge-offs
Current fiscal year	839	830
Year two	34	146
Year three	164	175
Year four	103	19
Year five	26	37
More than five years	18	5
Revolving	0	0
Revolving-Term	270	288
Total	1,454	1,500
Consumer Loans | Pass | Consumer real estate
Total Loan Balance
Current fiscal year	217,250	311,887
Year two	334,532	334,879
Year three	324,346	147,652
Year four	133,155	101,999
Year five	95,301	67,402
More than five years	223,799	183,283
Revolving	569,386	551,368
Revolving-Term	24,940	22,206
Total	1,922,709	1,720,676
Consumer Loans | Pass | Other consumer
Total Loan Balance
Current fiscal year	8,456	11,286
Year two	6,849	11,965
Year three	7,349	6,483
Year four	3,228	3,842
Year five	1,758	1,062
More than five years	468	526
Revolving	71,039	76,426
Revolving-Term	5,425	3,109
Total	104,572	114,699
Consumer Loans | Special mention | Consumer real estate
Total Loan Balance
Current fiscal year	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
More than five years	99	189
Revolving	0	0
Revolving-Term	0	0
Total	99	189
Consumer Loans | Special mention | Other consumer
Total Loan Balance
Current fiscal year	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five		0
More than five years	0	0
Revolving	0	0
Revolving-Term		0
Total	0	0
Consumer Loans | Substandard | Consumer real estate
Total Loan Balance
Current fiscal year	0	0
Year two	1,231	583
Year three	43	198
Year four	192	42
Year five	203	488
More than five years	5,564	6,322
Revolving	1,172	712
Revolving-Term	2,296	2,568
Total	10,701	10,913
Consumer Loans | Substandard | Other consumer
Total Loan Balance
Current fiscal year	0	0
Year two	0	0
Year three	0	24
Year four	21	5
Year five	10	20
More than five years	150	146
Revolving	0	0
Revolving-Term	4	3
Total	185	198
Consumer Loans | Doubtful | Consumer real estate
Total Loan Balance
Current fiscal year	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
More than five years	0	0
Revolving	0	0
Revolving-Term	0	0
Total	0	0
Consumer Loans | Doubtful | Other consumer
Total Loan Balance
Current fiscal year	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
More than five years	0	0
Revolving	0	0
Revolving-Term	0	0
Total	$ 0	$ 0