Loans - Financing Receivable, Gross Charge-Offs By Year of Origination (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 878,780
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	873,069
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	710,133
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	462,165
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	346,689
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	372,114
Financing Receivable, Revolving	2,386,818
Financing Receivable, Allowance for Credit Loss, Writeoff	2,144	$ 6,180
Commercial and Industrial Total Energy Loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	227,603
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	35,251
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	58,965
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	70,932
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	4,612
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	10,951
Financing Receivable, Revolving	521,034
Financing Receivable, Allowance for Credit Loss, Writeoff	0	0
Commercial Real Estate Buildings Land And Other Loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	408,729
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,560,879
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,745,471
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	1,302,714
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	798,561
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	1,390,645
Financing Receivable, Revolving	243,671
Financing Receivable, Allowance for Credit Loss, Writeoff	0
Construction Loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	242,949
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	440,037
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	598,799
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	289,714
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	28,028
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	1,353
Financing Receivable, Revolving	171,536
Financing Receivable, Allowance for Credit Loss, Writeoff	0
Total consumer real estate loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Writeoff	1,669	250
Consumer Loan [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Writeoff	8,257	6,942
Loans Receivable [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Writeoff	12,070	$ 13,372
Nonperforming Financial Instruments [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	5,279
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	21,871
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	3,754
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	6,597
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	1,029
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	9,936
Financing Receivable, Revolving	5,680
Financing Receivable, Revolving, Converted to Term Loan	17,369
Nonperforming Financial Instruments [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	11
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,059
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	394
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	2,941
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	935
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	2,719
Financing Receivable, Revolving	2,178
Financing Receivable, Revolving, Converted to Term Loan	14,209
Nonperforming Financial Instruments [Member] | Commercial and Industrial Total Energy Loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	5,268
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	56
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	1,321
Financing Receivable, Revolving	3,502
Financing Receivable, Revolving, Converted to Term Loan	146
Nonperforming Financial Instruments [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	19,812
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	3,360
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	3,656
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	3,184
Financing Receivable, Revolving	0
Financing Receivable, Revolving, Converted to Term Loan	0
Nonperforming Financial Instruments [Member] | Construction Loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	0
Financing Receivable, Revolving, Converted to Term Loan	0
Nonperforming Financial Instruments [Member] | Total consumer real estate loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	38
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	2,712
Financing Receivable, Revolving	0
Financing Receivable, Revolving, Converted to Term Loan	3,014
Nonperforming Financial Instruments [Member] | Consumer Loan [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	0
Financing Receivable, Revolving, Converted to Term Loan	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	1,958
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	5,639
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	784
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	696
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	10
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	327
Financing Receivable, Revolving	2,365
Financing Receivable, Revolving, Converted to Term Loan	291
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	96
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	572
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	439
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	6
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	13
Financing Receivable, Revolving	794
Financing Receivable, Revolving, Converted to Term Loan	224
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member] | Commercial and Industrial Total Energy Loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	0
Financing Receivable, Revolving, Converted to Term Loan	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	0
Financing Receivable, Revolving, Converted to Term Loan	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member] | Construction Loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	0
Financing Receivable, Revolving, Converted to Term Loan	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member] | Total consumer real estate loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	148
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	253
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	280
Financing Receivable, Revolving	921
Financing Receivable, Revolving, Converted to Term Loan	67
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member] | Consumer Loan [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	1,958
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	5,543
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	64
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	4
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	4
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	34
Financing Receivable, Revolving	650
Financing Receivable, Revolving, Converted to Term Loan	$ 0