Allowance for Credit Losses - Credit risk profile of loans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
Nonperforming loans past due			90 days
Current year	$ 168,676		$ 168,676		$ 410,976
Prior year	440,511		440,511		277,930
Two years before current year	287,223		287,223		468,277
Three years before current year	449,370		449,370		452,136
Four years before current year	418,067		418,067		208,251
Prior	611,495		611,495		486,299
Revolving Loans	172,013		172,013		211,048
Total loans	2,547,355		2,547,355		2,514,917
Current period gross charge offs, Total	2,928	$ 6,091	6,169	$ 9,283
Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	202,615		202,615		359,398
Prior year	316,235		316,235		268,003
Two years before current year	218,247		218,247		252,293
Three years before current year	208,463		208,463		119,148
Four years before current year	99,985		99,985		64,853
Prior	189,495		189,495		152,608
Revolving Loans	103,329		103,329		94,145
Total loans	1,338,369		1,338,369		1,310,448
Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	51		51		176
Prior year	466		466		477
Two years before current year	709		709		1,349
Three years before current year	1,091		1,091		771
Four years before current year	546		546		526
Prior	2,322		2,322		2,371
Revolving Loans	382		382		760
Total loans	5,567		5,567		6,430
Total other loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	202,666		202,666		359,574
Prior year	316,701		316,701		268,480
Two years before current year	218,956		218,956		253,642
Three years before current year	209,554		209,554		119,919
Four years before current year	100,531		100,531		65,379
Prior	191,817		191,817		154,979
Revolving Loans	103,711		103,711		94,905
Total loans	1,343,936		1,343,936		1,316,878
Residential | First Liens
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	32,942		32,942		64,953
Prior year	65,681		65,681		47,930
Two years before current year	45,769		45,769		89,205
Three years before current year	84,703		84,703		69,270
Four years before current year	65,013		65,013		37,771
Prior	162,173		162,173		138,824
Revolving Loans	1,454		1,454		2,279
Total loans	457,735		457,735		450,232
Current period gross charge offs, Prior			11		221
Current period gross charge offs, Total			11		221
Residential | First Liens | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	32,942		32,942		64,953
Prior year	65,681		65,681		47,930
Two years before current year	45,769		45,769		89,205
Three years before current year	84,703		84,703		69,090
Four years before current year	64,884		64,884		37,658
Prior	160,337		160,337		136,805
Revolving Loans	1,454		1,454		2,279
Total loans	455,770		455,770		447,920
Residential | First Liens | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Three years before current year					180
Four years before current year	129		129		113
Prior	1,836		1,836		2,019
Total loans	1,965		1,965		2,312
Residential | Home Equity
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	421		421		966
Prior year	914		914		562
Two years before current year	273		273		1,058
Three years before current year	813		813		31
Four years before current year	170		170		181
Prior	1,721		1,721		1,257
Revolving Loans	91,127		91,127		85,443
Total loans	95,439		95,439		89,498
Current period gross charge offs, 2022					22
Current period gross charge offs, 2021			22
Current period gross charge offs, Prior			19		28
Current period gross charge offs, Revolving Loans					51
Current period gross charge offs, Total			41		101
Residential | Home Equity | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	421		421		966
Prior year	914		914		562
Two years before current year	273		273		1,017
Three years before current year	777		777		31
Four years before current year	146		146		143
Prior	1,610		1,610		1,149
Revolving Loans	90,768		90,768		84,723
Total loans	94,909		94,909		88,591
Residential | Home Equity | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Two years before current year					41
Three years before current year	36		36
Four years before current year	24		24		38
Prior	111		111		108
Revolving Loans	359		359		720
Total loans	530		530		907
Residential | Junior Liens
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	8,157		8,157		16,989
Prior year	16,381		16,381		12,410
Two years before current year	11,139		11,139		12,631
Three years before current year	10,700		10,700		6,469
Four years before current year	5,529		5,529		5,260
Prior	12,342		12,342		9,375
Revolving Loans	2,777		2,777		1,578
Total loans	67,025		67,025		64,712
Current period gross charge offs, 2023					15
Current period gross charge offs, Prior			65
Current period gross charge offs, Total			65		15
Residential | Junior Liens | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	8,157		8,157		16,989
Prior year	16,381		16,381		12,371
Two years before current year	11,097		11,097		12,590
Three years before current year	10,680		10,680		6,431
Four years before current year	5,529		5,529		5,200
Prior	12,253		12,253		9,229
Revolving Loans	2,777		2,777		1,578
Total loans	66,874		66,874		64,388
Residential | Junior Liens | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Prior year					39
Two years before current year	42		42		41
Three years before current year	20		20		38
Four years before current year					60
Prior	89		89		146
Total loans	151		151		324
Residential | All Other Residential
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	5,537		5,537		17,542
Prior year	16,649		16,649		13,123
Two years before current year	8,592		8,592		6,960
Three years before current year	4,992		4,992		4,472
Four years before current year	3,918		3,918		633
Prior	2,133		2,133		1,595
Revolving Loans	378		378		53
Total loans	42,199		42,199		44,378
Current period gross charge offs, 2021					6
Current period gross charge offs, Total					6
Residential | All Other Residential | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	5,537		5,537		17,542
Prior year	16,649		16,649		13,123
Two years before current year	8,592		8,592		6,960
Three years before current year	4,992		4,992		4,392
Four years before current year	3,867		3,867		628
Prior	2,123		2,123		1,559
Revolving Loans	378		378		53
Total loans	42,138		42,138		44,257
Residential | All Other Residential | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Three years before current year					80
Four years before current year	51		51		5
Prior	10		10		36
Total loans	61		61		121
Consumer | Motor Vehicle
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	152,061		152,061		247,512
Prior year	208,697		208,697		187,480
Two years before current year	148,783		148,783		140,363
Three years before current year	106,123		106,123		37,441
Four years before current year	24,284		24,284		20,416
Prior	12,180		12,180		3,349
Revolving Loans	10		10		11
Total loans	652,138		652,138		636,572
Current period gross charge offs, 2024			32		478
Current period gross charge offs, 2023			966		2,692
Current period gross charge offs, 2022			1,107		4,839
Current period gross charge offs, 2021			2,274		1,751
Current period gross charge offs, 2020			437		587
Current period gross charge offs, Prior			191		97
Current period gross charge offs, Total			5,007		10,444
Consumer | Motor Vehicle | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	152,010		152,010		247,368
Prior year	208,316		208,316		187,134
Two years before current year	148,240		148,240		139,251
Three years before current year	105,094		105,094		37,043
Four years before current year	24,013		24,013		20,130
Prior	11,927		11,927		3,290
Revolving Loans	10		10		11
Total loans	649,610		649,610		634,227
Consumer | Motor Vehicle | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	51		51		144
Prior year	381		381		346
Two years before current year	543		543		1,112
Three years before current year	1,029		1,029		398
Four years before current year	271		271		286
Prior	253		253		59
Total loans	2,528		2,528		2,345
Consumer | All Other Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	3,548		3,548		11,612
Prior year	8,379		8,379		6,975
Two years before current year	4,400		4,400		3,425
Three years before current year	2,223		2,223		2,236
Four years before current year	1,617		1,617		1,118
Prior	1,268		1,268		579
Revolving Loans	7,965		7,965		5,541
Total loans	29,400		29,400		31,486
Current period gross charge offs, 2024					50
Current period gross charge offs, 2023			102		197
Current period gross charge offs, 2022			71		121
Current period gross charge offs, 2021			53		22
Current period gross charge offs, 2020			24		16
Current period gross charge offs, Prior			3		24
Current period gross charge offs, Revolving Loans			93		182
Current period gross charge offs, Total			346		612
Consumer | All Other Consumer | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	3,548		3,548		11,580
Prior year	8,294		8,294		6,883
Two years before current year	4,276		4,276		3,270
Three years before current year	2,217		2,217		2,161
Four years before current year	1,546		1,546		1,094
Prior	1,245		1,245		576
Revolving Loans	7,942		7,942		5,501
Total loans	29,068		29,068		31,065
Consumer | All Other Consumer | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current year					32
Prior year	85		85		92
Two years before current year	124		124		155
Three years before current year	6		6		75
Four years before current year	71		71		24
Prior	23		23		3
Revolving Loans	23		23		40
Total loans	$ 332		$ 332		$ 421