Loans (Credit Quality Indicators Vintage) (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]
Term loans amortized cost, current year	$ 160,666		$ 160,666		$ 878,981
Term loans amortized cost, prior year	895,688		895,688		1,551,627
Term loans amortized cost, two years ago	1,555,941		1,555,941		1,144,330
Term loans amortized cost, three years ago	1,107,519		1,107,519		478,623
Term loans amortized cost, four years ago	458,035		458,035		372,009
Term loans amortized cost, five years ago or more	1,091,928		1,091,928		831,226
Revolving loans amortized cost	344,965		344,965		375,764
Revolving loans converted to term loans	14,360		14,360		15,146
Total	5,629,102		5,629,102		5,647,706
Gross charge-offs, current year			118		196
Gross charge-offs, prior year			0		0
Gross charge-offs, two years ago			0		8
Gross charge-offs, three years ago			0		0
Gross charge-offs, four years ago			2		0
Gross charge-offs, five years ago or more			3		373
Gross charge-offs, revolving loans			0		0
Gross charge-offs, revolving loans converted to term loans			0		0
Total gross charge-offs	53	$ 52	123	$ 113	577
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	89,158		89,158		348,969
Term loans amortized cost, prior year	398,322		398,322		598,946
Term loans amortized cost, two years ago	625,220		625,220		414,898
Term loans amortized cost, three years ago	416,934		416,934		168,451
Term loans amortized cost, four years ago	160,985		160,985		181,982
Term loans amortized cost, five years ago or more	487,134		487,134		349,986
Revolving loans amortized cost	13,234		13,234		42,095
Revolving loans converted to term loans	1,009		1,009		1,032
Total	2,191,996		2,191,996		2,106,359
Gross charge-offs, current year			0		0
Gross charge-offs, prior year			0		0
Gross charge-offs, two years ago			0		0
Gross charge-offs, three years ago			0		0
Gross charge-offs, four years ago			0		0
Gross charge-offs, five years ago or more			0		373
Gross charge-offs, revolving loans			0		0
Gross charge-offs, revolving loans converted to term loans			0		0
Total gross charge-offs	0	0	0	0	373
Commercial real estate | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	89,158		89,158		327,139
Term loans amortized cost, prior year	390,442		390,442		598,946
Term loans amortized cost, two years ago	625,220		625,220		396,468
Term loans amortized cost, three years ago	397,167		397,167		168,451
Term loans amortized cost, four years ago	160,985		160,985		167,484
Term loans amortized cost, five years ago or more	466,860		466,860		333,356
Revolving loans amortized cost	13,234		13,234		42,095
Revolving loans converted to term loans	1,009		1,009		1,032
Total	2,144,075		2,144,075		2,034,971
Commercial real estate | Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	0		0		0
Term loans amortized cost, prior year	0		0		0
Term loans amortized cost, two years ago	0		0		0
Term loans amortized cost, three years ago	0		0		0
Term loans amortized cost, four years ago	0		0		0
Term loans amortized cost, five years ago or more	6,312		6,312		16,630
Revolving loans amortized cost	0		0		0
Revolving loans converted to term loans	0		0		0
Total	6,312		6,312		16,630
Commercial real estate | Classified [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	0		0		21,830
Term loans amortized cost, prior year	7,880		7,880		0
Term loans amortized cost, two years ago	0		0		18,430
Term loans amortized cost, three years ago	19,767		19,767		0
Term loans amortized cost, four years ago	0		0		14,498
Term loans amortized cost, five years ago or more	13,962		13,962		0
Revolving loans amortized cost	0		0		0
Revolving loans converted to term loans	0		0		0
Total	41,609		41,609		54,758
Commercial & industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	20,415		20,415		66,726
Term loans amortized cost, prior year	52,570		52,570		125,712
Term loans amortized cost, two years ago	121,051		121,051		52,471
Term loans amortized cost, three years ago	37,888		37,888		49,812
Term loans amortized cost, four years ago	48,225		48,225		73,739
Term loans amortized cost, five years ago or more	178,984		178,984		145,361
Revolving loans amortized cost	98,414		98,414		90,664
Revolving loans converted to term loans	528		528		587
Total	558,075		558,075		605,072
Gross charge-offs, current year			20		37
Gross charge-offs, prior year			0		0
Gross charge-offs, two years ago			0		0
Gross charge-offs, three years ago			0		0
Gross charge-offs, four years ago			0		0
Gross charge-offs, five years ago or more			0		0
Gross charge-offs, revolving loans			0		0
Gross charge-offs, revolving loans converted to term loans			0		0
Total gross charge-offs	12	9	20	20	37
Commercial & industrial | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	20,415		20,415		55,607
Term loans amortized cost, prior year	52,570		52,570		124,894
Term loans amortized cost, two years ago	120,234		120,234		52,282
Term loans amortized cost, three years ago	37,713		37,713		49,812
Term loans amortized cost, four years ago	48,225		48,225		72,876
Term loans amortized cost, five years ago or more	178,164		178,164		145,361
Revolving loans amortized cost	98,414		98,414		90,664
Revolving loans converted to term loans	528		528		587
Total	556,263		556,263		592,083
Commercial & industrial | Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	0		0		11,119
Term loans amortized cost, prior year	0		0		0
Term loans amortized cost, two years ago	0		0		0
Term loans amortized cost, three years ago	0		0		0
Term loans amortized cost, four years ago	0		0		181
Term loans amortized cost, five years ago or more	178		178		0
Revolving loans amortized cost	0		0		0
Revolving loans converted to term loans	0		0		0
Total	178		178		11,300
Commercial & industrial | Classified [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	0		0		0
Term loans amortized cost, prior year	0		0		818
Term loans amortized cost, two years ago	817		817		189
Term loans amortized cost, three years ago	175		175		0
Term loans amortized cost, four years ago	0		0		682
Term loans amortized cost, five years ago or more	642		642		0
Revolving loans amortized cost	0		0		0
Revolving loans converted to term loans	0		0		0
Total	1,634		1,634		1,689
Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	41,093		41,093		431,563
Term loans amortized cost, prior year	419,268		419,268		808,442
Term loans amortized cost, two years ago	792,516		792,516		666,447
Term loans amortized cost, three years ago	643,854		643,854		256,440
Term loans amortized cost, four years ago	245,366		245,366		114,056
Term loans amortized cost, five years ago or more	416,436		416,436		327,530
Revolving loans amortized cost	0		0		0
Revolving loans converted to term loans	0		0		0
Total	2,558,533		2,558,533		2,604,478
Gross charge-offs, current year			0		0
Gross charge-offs, prior year			0		0
Gross charge-offs, two years ago			0		0
Gross charge-offs, three years ago			0		0
Gross charge-offs, four years ago			0		0
Gross charge-offs, five years ago or more			0		0
Gross charge-offs, revolving loans			0		0
Gross charge-offs, revolving loans converted to term loans			0		0
Total gross charge-offs	0	0	0	0	0
Residential real estate | Current [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	41,093		41,093		431,563
Term loans amortized cost, prior year	419,268		419,268		808,442
Term loans amortized cost, two years ago	792,516		792,516		666,447
Term loans amortized cost, three years ago	643,854		643,854		255,554
Term loans amortized cost, four years ago	244,486		244,486		113,462
Term loans amortized cost, five years ago or more	408,782		408,782		320,894
Revolving loans amortized cost	0		0		0
Revolving loans converted to term loans	0		0		0
Total	2,549,999		2,549,999		2,596,362
Residential real estate | Past Due [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	0		0		0
Term loans amortized cost, prior year	0		0		0
Term loans amortized cost, two years ago	0		0		0
Term loans amortized cost, three years ago	0		0		886
Term loans amortized cost, four years ago	880		880		594
Term loans amortized cost, five years ago or more	7,654		7,654		6,636
Revolving loans amortized cost	0		0		0
Revolving loans converted to term loans	0		0		0
Total	8,534		8,534		8,116
Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	7,107		7,107		24,925
Term loans amortized cost, prior year	20,104		20,104		14,997
Term loans amortized cost, two years ago	13,958		13,958		6,829
Term loans amortized cost, three years ago	6,519		6,519		2,919
Term loans amortized cost, four years ago	2,556		2,556		2,112
Term loans amortized cost, five years ago or more	5,899		5,899		4,525
Revolving loans amortized cost	233,061		233,061		242,760
Revolving loans converted to term loans	12,823		12,823		13,527
Total	302,027		302,027		312,594
Gross charge-offs, current year			0		0
Gross charge-offs, prior year			0		0
Gross charge-offs, two years ago			0		0
Gross charge-offs, three years ago			0		0
Gross charge-offs, four years ago			0		0
Gross charge-offs, five years ago or more			0		0
Gross charge-offs, revolving loans			0		0
Gross charge-offs, revolving loans converted to term loans			0		0
Total gross charge-offs	0	0	0	0	0
Home equity | Current [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	7,107		7,107		24,925
Term loans amortized cost, prior year	20,104		20,104		14,997
Term loans amortized cost, two years ago	13,958		13,958		6,829
Term loans amortized cost, three years ago	6,519		6,519		2,919
Term loans amortized cost, four years ago	2,414		2,414		1,982
Term loans amortized cost, five years ago or more	5,104		5,104		3,696
Revolving loans amortized cost	232,243		232,243		241,459
Revolving loans converted to term loans	11,254		11,254		12,591
Total	298,703		298,703		309,398
Home equity | Past Due [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	0		0		0
Term loans amortized cost, prior year	0		0		0
Term loans amortized cost, two years ago	0		0		0
Term loans amortized cost, three years ago	0		0		0
Term loans amortized cost, four years ago	142		142		130
Term loans amortized cost, five years ago or more	795		795		829
Revolving loans amortized cost	818		818		1,301
Revolving loans converted to term loans	1,569		1,569		936
Total	3,324		3,324		3,196
Other
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	2,893		2,893		6,798
Term loans amortized cost, prior year	5,424		5,424		3,530
Term loans amortized cost, two years ago	3,196		3,196		3,685
Term loans amortized cost, three years ago	2,324		2,324		1,001
Term loans amortized cost, four years ago	903		903		120
Term loans amortized cost, five years ago or more	3,475		3,475		3,824
Revolving loans amortized cost	256		256		245
Revolving loans converted to term loans	0		0		0
Total	18,471		18,471		19,203
Gross charge-offs, current year			98		159
Gross charge-offs, prior year			0		0
Gross charge-offs, two years ago			0		8
Gross charge-offs, three years ago			0		0
Gross charge-offs, four years ago			2		0
Gross charge-offs, five years ago or more			3		0
Gross charge-offs, revolving loans			0		0
Gross charge-offs, revolving loans converted to term loans			0		0
Total gross charge-offs	41	$ 43	103	$ 93	167
Other | Current [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	2,874		2,874		6,777
Term loans amortized cost, prior year	5,424		5,424		3,530
Term loans amortized cost, two years ago	3,196		3,196		3,685
Term loans amortized cost, three years ago	2,324		2,324		1,001
Term loans amortized cost, four years ago	903		903		120
Term loans amortized cost, five years ago or more	3,474		3,474		3,824
Revolving loans amortized cost	256		256		243
Revolving loans converted to term loans	0		0		0
Total	18,451		18,451		19,180
Other | Past Due [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year	19		19		21
Term loans amortized cost, prior year	0		0		0
Term loans amortized cost, two years ago	0		0		0
Term loans amortized cost, three years ago	0		0		0
Term loans amortized cost, four years ago	0		0		0
Term loans amortized cost, five years ago or more	1		1		0
Revolving loans amortized cost	0		0		2
Revolving loans converted to term loans	0		0		0
Total	$ 20		$ 20		$ 23