Loans (Credit Quality Indicators Vintage) (Details) - USD ($) $ in Thousands		3 Months Ended			12 Months Ended
		Mar. 31, 2026		Mar. 31, 2025	Dec. 31, 2025
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	[1]	$ 5,014,885			$ 5,134,388
Gross charge-offs, current year		83			372
Gross charge-offs, prior year		0			0
Gross charge-offs, two years ago		0			8,346
Gross charge-offs, three years ago		1			0
Gross charge-offs, four years ago		0			0
Gross charge-offs, five years ago or more		0			6,017
Gross charge-offs, revolving loans		0			0
Gross charge-offs, revolving loans converted to term loans		0			0
Total gross charge-offs		84		$ 2,522	14,735
Basis adjustment associated with fair value hedges		(923)			(335)
Financing Receivable
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		102,711			739,363
Term loans amortized cost, prior year		676,951			206,495
Term loans amortized cost, two years ago		197,114			743,308
Term loans amortized cost, three years ago		682,863			1,348,951
Term loans amortized cost, four years ago		1,323,023			676,185
Term loans amortized cost, five years ago or more		1,698,445			1,090,180
Revolving loans amortized cost		318,060			313,376
Revolving loans converted to term loans		16,641			16,865
Total loans		5,015,808			5,134,723
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		58,895			465,820
Term loans amortized cost, prior year		403,876			102,312
Term loans amortized cost, two years ago		98,630			338,922
Term loans amortized cost, three years ago		294,287			517,754
Term loans amortized cost, four years ago		507,056			302,383
Term loans amortized cost, five years ago or more		711,828			446,426
Revolving loans amortized cost		9,303			9,426
Revolving loans converted to term loans		929			942
Total loans	[2]	2,084,804			2,183,985
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			5,715
Gross charge-offs, revolving loans		0			0
Gross charge-offs, revolving loans converted to term loans		0			0
Total gross charge-offs		0		2,450	5,715
Commercial real estate | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		58,895			432,404
Term loans amortized cost, prior year		369,781			102,312
Term loans amortized cost, two years ago		98,630			338,922
Term loans amortized cost, three years ago		282,310			490,011
Term loans amortized cost, four years ago		475,205			302,383
Term loans amortized cost, five years ago or more		701,930			438,112
Revolving loans amortized cost		9,303			9,426
Revolving loans converted to term loans		929			942
Total loans		1,996,983			2,114,512
Commercial real estate | Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		0			33,416
Term loans amortized cost, prior year		27,521			0
Term loans amortized cost, two years ago		0			0
Term loans amortized cost, three years ago		11,977			27,743
Term loans amortized cost, four years ago		9,502			0
Term loans amortized cost, five years ago or more		3,773			2,157
Revolving loans amortized cost		0			0
Revolving loans converted to term loans		0			0
Total loans		52,773			63,316
Commercial real estate | Classified [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		0			0
Term loans amortized cost, prior year		6,574			0
Term loans amortized cost, two years ago		0			0
Term loans amortized cost, three years ago		0			0
Term loans amortized cost, four years ago		22,349			0
Term loans amortized cost, five years ago or more		6,125			6,157
Revolving loans amortized cost		0			0
Revolving loans converted to term loans		0			0
Total loans		35,048			6,157
Commercial & industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		9,120			91,092
Term loans amortized cost, prior year		91,604			40,344
Term loans amortized cost, two years ago		39,673			54,047
Term loans amortized cost, three years ago		53,572			129,288
Term loans amortized cost, four years ago		127,392			21,278
Term loans amortized cost, five years ago or more		175,145			163,572
Revolving loans amortized cost		71,354			64,146
Revolving loans converted to term loans		317			315
Total loans	[3]	568,177			564,082
Gross charge-offs, current year		17			49
Gross charge-offs, prior year		0			0
Gross charge-offs, two years ago		0			8,345
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			299
Gross charge-offs, revolving loans		0			0
Gross charge-offs, revolving loans converted to term loans		0			0
Total gross charge-offs		17		7	8,693
Commercial & industrial | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		9,120			87,523
Term loans amortized cost, prior year		91,604			39,556
Term loans amortized cost, two years ago		38,889			54,047
Term loans amortized cost, three years ago		53,572			125,846
Term loans amortized cost, four years ago		127,057			20,057
Term loans amortized cost, five years ago or more		174,893			159,707
Revolving loans amortized cost		70,653			58,146
Revolving loans converted to term loans		317			315
Total loans		566,105			545,197
Commercial & industrial | Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		0			3,569
Term loans amortized cost, prior year		0			788
Term loans amortized cost, two years ago		784			0
Term loans amortized cost, three years ago		0			3,442
Term loans amortized cost, four years ago		335			1,095
Term loans amortized cost, five years ago or more		126			3,865
Revolving loans amortized cost		701			6,000
Revolving loans converted to term loans		0			0
Total loans		1,946			18,759
Commercial & industrial | Classified [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		0			0
Term loans amortized cost, prior year		0			0
Term loans amortized cost, two years ago		0			0
Term loans amortized cost, three years ago		0			0
Term loans amortized cost, four years ago		0			126
Term loans amortized cost, five years ago or more		126			0
Revolving loans amortized cost		0			0
Revolving loans converted to term loans		0			0
Total loans		126			126
Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	[4]	2,029,092			2,050,399
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
Residential real estate | Financing Receivable
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		30,985			161,291
Term loans amortized cost, prior year		161,148			50,709
Term loans amortized cost, two years ago		46,821			332,253
Term loans amortized cost, three years ago		317,827			690,150
Term loans amortized cost, four years ago		677,142			345,581
Term loans amortized cost, five years ago or more		796,092			470,750
Revolving loans amortized cost		0			0
Revolving loans converted to term loans		0			0
Total loans		2,030,015			2,050,734
Residential real estate | Current [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		30,985			161,291
Term loans amortized cost, prior year		161,148			50,709
Term loans amortized cost, two years ago		46,821			332,253
Term loans amortized cost, three years ago		317,827			690,150
Term loans amortized cost, four years ago		676,119			345,038
Term loans amortized cost, five years ago or more		790,488	[5]		462,198
Revolving loans amortized cost		0			0
Revolving loans converted to term loans		0			0
Total loans		2,023,388	[5]		2,041,639
Residential real estate | Past Due [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		0			0
Term loans amortized cost, prior year		0			0
Term loans amortized cost, two years ago		0			0
Term loans amortized cost, three years ago		0			0
Term loans amortized cost, four years ago		1,023			543
Term loans amortized cost, five years ago or more		5,604			8,552
Revolving loans amortized cost		0			0
Revolving loans converted to term loans		0			0
Total loans		6,627			9,095
Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		2,885			16,839
Term loans amortized cost, prior year		16,260			10,542
Term loans amortized cost, two years ago		9,534			14,720
Term loans amortized cost, three years ago		14,176			9,969
Term loans amortized cost, four years ago		9,695			5,327
Term loans amortized cost, five years ago or more		11,269			6,309
Revolving loans amortized cost		237,139			239,548
Revolving loans converted to term loans		15,395			15,608
Total loans		316,353			318,862
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
Home equity | Current [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		2,885			16,839
Term loans amortized cost, prior year		16,260			10,508
Term loans amortized cost, two years ago		9,461			14,662
Term loans amortized cost, three years ago		13,964			9,969
Term loans amortized cost, four years ago		9,646			5,190
Term loans amortized cost, five years ago or more		10,877			6,086
Revolving loans amortized cost		236,681			238,734
Revolving loans converted to term loans		13,833			15,267
Total loans		313,607			317,255
Home equity | Past Due [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		0			0
Term loans amortized cost, prior year		0			34
Term loans amortized cost, two years ago		73			58
Term loans amortized cost, three years ago		212			0
Term loans amortized cost, four years ago		49			137
Term loans amortized cost, five years ago or more		392			223
Revolving loans amortized cost		458			814
Revolving loans converted to term loans		1,562			341
Total loans		2,746			1,607
Other
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		826			4,321
Term loans amortized cost, prior year		4,063			2,588
Term loans amortized cost, two years ago		2,456			3,366
Term loans amortized cost, three years ago		3,001			1,790
Term loans amortized cost, four years ago		1,738			1,616
Term loans amortized cost, five years ago or more		4,111			3,123
Revolving loans amortized cost		264			256
Revolving loans converted to term loans		0			0
Total loans	[6]	16,459			17,060
Gross charge-offs, current year		66			323
Gross charge-offs, prior year		0			0
Gross charge-offs, two years ago		0			1
Gross charge-offs, three years ago		1			0
Gross charge-offs, four years ago		0			0
Gross charge-offs, five years ago or more		0			3
Gross charge-offs, revolving loans		0			0
Gross charge-offs, revolving loans converted to term loans		0			0
Total gross charge-offs		67		$ 65	327
Other | Current [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		802			4,295
Term loans amortized cost, prior year		4,058			2,588
Term loans amortized cost, two years ago		2,456			3,366
Term loans amortized cost, three years ago		3,001			1,790
Term loans amortized cost, four years ago		1,738			1,616
Term loans amortized cost, five years ago or more		4,110			3,123
Revolving loans amortized cost		263			256
Revolving loans converted to term loans		0			0
Total loans		16,428			17,034
Other | Past Due [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans amortized cost, current year		24			26
Term loans amortized cost, prior year		5			0
Term loans amortized cost, two years ago		0			0
Term loans amortized cost, three years ago		0			0
Term loans amortized cost, four years ago		0			0
Term loans amortized cost, five years ago or more		1			0
Revolving loans amortized cost		1			0
Revolving loans converted to term loans		0			0
Total loans		$ 31			$ 26

[1] Includes net unamortized loan origination costs of $11.3 million and $11.0 million, respectively, at March 31, 2026 and December 31, 2025 and net unamortized premiums on loans purchased from and serviced by other financial institutions of $193 thousand and $198 thousand, respectively, at March 31, 2026 and December 31, 2025.

[2] CRE consists of commercial mortgages primarily secured by non-owner occupied income-producing property, as well as construction and development loans. Construction and development loans are made to businesses for land development or the on-site construction of industrial, commercial, or residential buildings.

[3] C&I consists of loans to businesses and individuals, a portion of which are fully or partially collateralized by owner occupied real estate.

[4] Residential real estate consists of mortgage and homeowner construction loans secured by one- to four-family residential properties. Also, includes negative basis adjustments associated with fair value hedges of $923 thousand and $335 thousand, respectively, at March 31, 2026 and December 31, 2025. See Note 6 for additional disclosure.

[5] Excludes a $923 thousand negative basis adjustment associated with fair value hedges. See Note 6 for additional disclosure.

[6] Other consists of loans to individuals secured by general aviation aircraft and other personal installment loans.