Allowance for Credit Losses - Credit risk profile of loans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Nonperforming loans past due			90 days
Current year	$ 158,376		$ 158,376		$ 255,765
Prior year	244,258		244,258		458,326
Two years before current year	454,903		454,903		361,138
Three years before current year	338,585		338,585		210,908
Four years before current year	191,404		191,404		98,537
Prior	476,704		476,704		446,015
Revolving Loans	154,186		154,186		177,744
Total loans	2,018,416		2,018,416		2,008,433
Current period gross charge offs, Total	6,091	$ 3,543	9,283	$ 7,919
Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	176,067		176,067		348,183
Prior year	305,584		305,584		317,948
Two years before current year	270,809		270,809		151,284
Three years before current year	127,292		127,292		91,864
Four years before current year	74,246		74,246		33,181
Prior	146,021		146,021		131,427
Revolving Loans	73,274		73,274		72,484
Total loans	1,173,293		1,173,293		1,146,371
Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	4		4		232
Prior year	574		574		1,189
Two years before current year	1,005		1,005		756
Three years before current year	859		859		757
Four years before current year	583		583		598
Prior	1,974		1,974		1,735
Revolving Loans	112		112		1
Total loans	5,111		5,111		5,268
Total other loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	176,071		176,071		348,415
Prior year	306,158		306,158		319,137
Two years before current year	271,814		271,814		152,040
Three years before current year	128,151		128,151		92,621
Four years before current year	74,829		74,829		33,779
Prior	147,995		147,995		133,162
Revolving Loans	73,386		73,386		72,485
Total loans	1,178,404		1,178,404		1,151,639
Residential | First Liens
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	24,841		24,841		49,146
Prior year	47,700		47,700		71,073
Two years before current year	68,600		68,600		65,232
Three years before current year	62,265		62,265		36,816
Four years before current year	34,456		34,456		15,242
Prior	125,282		125,282		119,591
Revolving Loans	671		671		1,066
Total loans	363,815		363,815		358,166
Current period gross charge offs, Prior			14		167
Current period gross charge offs, Total			14		167
Residential | First Liens | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	24,841		24,841		49,146
Prior year	47,700		47,700		70,952
Two years before current year	68,600		68,600		65,232
Three years before current year	61,857		61,857		36,751
Four years before current year	34,392		34,392		15,185
Prior	124,100		124,100		118,087
Revolving Loans	671		671		1,066
Total loans	362,161		362,161		356,419
Residential | First Liens | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Prior year					121
Three years before current year	408		408		65
Four years before current year	64		64		57
Prior	1,182		1,182		1,504
Total loans	1,654		1,654		1,747
Residential | Home Equity
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	174		174		61
Prior year	124		124		90
Two years before current year	129		129
Three years before current year	29		29		24
Four years before current year	106		106		378
Prior	1,416		1,416		926
Revolving Loans	65,534		65,534		64,102
Total loans	67,512		67,512		65,581
Current period gross charge offs, 2022			22
Current period gross charge offs, Revolving Loans			20
Current period gross charge offs, Total			42
Residential | Home Equity | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	174		174		61
Prior year	124		124		68
Two years before current year	54		54
Three years before current year	29		29		7
Four years before current year	90		90		378
Prior	1,333		1,333		866
Revolving Loans	65,461		65,461		64,102
Total loans	67,265		67,265		65,482
Residential | Home Equity | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Prior year					22
Two years before current year	75		75
Three years before current year					17
Four years before current year	16		16
Prior	83		83		60
Revolving Loans	73		73
Total loans	247		247		99
Residential | Junior Liens
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	6,875		6,875		15,050
Prior year	13,795		13,795		15,484
Two years before current year	13,889		13,889		8,293
Three years before current year	7,245		7,245		5,661
Four years before current year	5,589		5,589		4,280
Prior	10,698		10,698		8,197
Revolving Loans	1,501		1,501		1,698
Total loans	59,592		59,592		58,663
Current period gross charge offs, 2020					24
Current period gross charge offs, Prior					24
Current period gross charge offs, Total					48
Residential | Junior Liens | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	6,875		6,875		15,050
Prior year	13,693		13,693		15,431
Two years before current year	13,889		13,889		8,248
Three years before current year	7,245		7,245		5,557
Four years before current year	5,525		5,525		4,280
Prior	10,532		10,532		8,094
Revolving Loans	1,501		1,501		1,698
Total loans	59,260		59,260		58,358
Residential | Junior Liens | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Prior year	102		102		53
Two years before current year					45
Three years before current year					104
Four years before current year	64		64
Prior	166		166		103
Total loans	332		332		305
Residential | All Other Residential
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	498		498		6,432
Prior year	7,385		7,385		9,477
Two years before current year	7,717		7,717		3,146
Three years before current year	2,703		2,703		421
Four years before current year	398		398		1,031
Prior	2,419		2,419		1,549
Revolving Loans	234		234		415
Total loans	21,354		21,354		22,471
Current period gross charge offs, Prior					1
Current period gross charge offs, Total					1
Residential | All Other Residential | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	498		498		6,432
Prior year	7,385		7,385		9,477
Two years before current year	7,717		7,717		3,100
Three years before current year	2,703		2,703		421
Four years before current year	398		398		641
Prior	1,994		1,994		1,511
Revolving Loans	234		234		415
Total loans	20,929		20,929		21,997
Residential | All Other Residential | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Two years before current year					46
Four years before current year					390
Prior	425		425		38
Total loans	425		425		474
Consumer | Motor Vehicle
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	137,535		137,535		265,165
Prior year	228,071		228,071		216,098
Two years before current year	176,621		176,621		71,446
Three years before current year	53,078		53,078		47,471
Four years before current year	32,574		32,574		12,172
Prior	7,351		7,351		2,207
Revolving Loans	12		12
Total loans	635,242		635,242		614,559
Current period gross charge offs, 2024			49		841
Current period gross charge offs, 2023			1,369		7,722
Current period gross charge offs, 2022			2,408		3,101
Current period gross charge offs, 2021			987		1,448
Current period gross charge offs, 2020			354		499
Current period gross charge offs, Prior			57		174
Current period gross charge offs, Total			5,224		13,785
Consumer | Motor Vehicle | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	137,531		137,531		264,933
Prior year	227,663		227,663		215,125
Two years before current year	175,727		175,727		70,926
Three years before current year	52,729		52,729		46,939
Four years before current year	32,161		32,161		12,038
Prior	7,238		7,238		2,177
Revolving Loans	12		12
Total loans	633,061		633,061		612,138
Consumer | Motor Vehicle | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	4		4		232
Prior year	408		408		973
Two years before current year	894		894		520
Three years before current year	349		349		532
Four years before current year	413		413		134
Prior	113		113		30
Total loans	2,181		2,181		2,421
Consumer | All Other Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	6,148		6,148		12,561
Prior year	9,083		9,083		6,915
Two years before current year	4,858		4,858		3,923
Three years before current year	2,831		2,831		2,228
Four years before current year	1,706		1,706		676
Prior	829		829		692
Revolving Loans	5,434		5,434		5,204
Total loans	30,889		30,889		32,199
Current period gross charge offs, 2024					61
Current period gross charge offs, 2023			62		213
Current period gross charge offs, 2022			57		61
Current period gross charge offs, 2021			5		37
Current period gross charge offs, 2020			7		3
Current period gross charge offs, Prior			9		5
Current period gross charge offs, Revolving Loans			84		149
Current period gross charge offs, Total			224		529
Consumer | All Other Consumer | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	6,148		6,148		12,561
Prior year	9,019		9,019		6,895
Two years before current year	4,822		4,822		3,778
Three years before current year	2,729		2,729		2,189
Four years before current year	1,680		1,680		659
Prior	824		824		692
Revolving Loans	5,395		5,395		5,203
Total loans	30,617		30,617		31,977
Consumer | All Other Consumer | Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Prior year	64		64		20
Two years before current year	36		36		145
Three years before current year	102		102		39
Four years before current year	26		26		17
Prior	5		5
Revolving Loans	39		39		1
Total loans	$ 272		$ 272		$ 222