Loans and Allowance for Credit Losses for Loans - Amortized Cost In Those Loan Classes Based on Payment Activity by Origination Year (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 49,877,248		$ 49,877,248		$ 46,917,200
Gross loan charge-offs
Total	11,327	$ 5,267	43,900	$ 7,862
90 Days or More Past Due Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	15,002		15,002		26,587
Residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	369,607		369,607		1,302,279
Year two, fiscal year before current fiscal year	1,304,505		1,304,505		1,502,819
Year three, two years before current fiscal year	1,524,988		1,524,988		571,607
Year four, three years before current fiscal year	562,263		562,263		502,032
Year five, four years before current fiscal year	456,260		456,260		340,938
More than five years before current fiscal year	1,268,750		1,268,750		1,078,169
Revolving Loans Amortized Cost Basis	73,983		73,983		66,706
Revolving Loans Converted to Term Loans	0		0		0
Total	5,560,356		5,560,356		5,364,550
Gross loan charge-offs
Total	149	1	149	27
Residential mortgage | 90 Days or More Past Due Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,165		1,165		1,866
Residential mortgage | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	369,607		369,607		1,302,279
Year two, fiscal year before current fiscal year	1,304,327		1,304,327		1,502,622
Year three, two years before current fiscal year	1,524,988		1,524,988		571,390
Year four, three years before current fiscal year	562,263		562,263		500,197
Year five, four years before current fiscal year	455,463		455,463		338,062
More than five years before current fiscal year	1,263,659		1,263,659		1,073,995
Revolving Loans Amortized Cost Basis	73,983		73,983		66,706
Revolving Loans Converted to Term Loans	0		0		0
Total	5,554,290		5,554,290		5,355,251
Residential mortgage | Non-Performing Loans | 90 Days or More Past Due Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	0		0		0
Year two, fiscal year before current fiscal year	178		178		197
Year three, two years before current fiscal year	0		0		217
Year four, three years before current fiscal year	0		0		1,835
Year five, four years before current fiscal year	797		797		2,876
More than five years before current fiscal year	5,091		5,091		4,174
Revolving Loans Amortized Cost Basis	0		0		0
Revolving Loans Converted to Term Loans	0		0		0
Total	6,066		6,066		9,299
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	242,632		242,632		795,819
Year two, fiscal year before current fiscal year	699,954		699,954		547,709
Year three, two years before current fiscal year	447,925		447,925		217,412
Year four, three years before current fiscal year	169,300		169,300		178,742
Year five, four years before current fiscal year	137,005		137,005		93,100
More than five years before current fiscal year	101,954		101,954		74,268
Revolving Loans Amortized Cost Basis	1,582,946		1,582,946		1,368,622
Revolving Loans Converted to Term Loans	39,034		39,034		39,280
Total	3,420,750		3,420,750		3,314,952
Gross loan charge-offs
Total	1,040	$ 726	1,868	$ 1,551
Consumer | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	19,442		19,442		47,084
Year two, fiscal year before current fiscal year	45,601		45,601		12,432
Year three, two years before current fiscal year	11,873		11,873		4,592
Year four, three years before current fiscal year	4,326		4,326		5,024
Year five, four years before current fiscal year	4,660		4,660		5,581
More than five years before current fiscal year	17,396		17,396		13,007
Revolving Loans Amortized Cost Basis	393,161		393,161		376,884
Revolving Loans Converted to Term Loans	39,034		39,034		39,280
Total	535,493		535,493		503,884
Consumer | Automobile
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	205,217		205,217		724,595
Year two, fiscal year before current fiscal year	633,374		633,374		525,133
Year three, two years before current fiscal year	437,601		437,601		204,614
Year four, three years before current fiscal year	161,245		161,245		166,283
Year five, four years before current fiscal year	123,625		123,625		80,113
More than five years before current fiscal year	71,813		71,813		45,487
Revolving Loans Amortized Cost Basis	0		0		0
Revolving Loans Converted to Term Loans	0		0		0
Total	1,632,875		1,632,875		1,746,225
Consumer | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	17,973		17,973		24,140
Year two, fiscal year before current fiscal year	20,979		20,979		10,144
Year three, two years before current fiscal year	(1,549)		(1,549)		8,206
Year four, three years before current fiscal year	3,729		3,729		7,435
Year five, four years before current fiscal year	8,720		8,720		7,406
More than five years before current fiscal year	12,745		12,745		15,774
Revolving Loans Amortized Cost Basis	1,189,785		1,189,785		991,738
Revolving Loans Converted to Term Loans	0		0		0
Total	1,252,382		1,252,382		1,064,843
Consumer | 90 Days or More Past Due Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,006		1,006		47
Consumer | 90 Days or More Past Due Loans | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0		0		0
Consumer | 90 Days or More Past Due Loans | Automobile
Financing Receivable, Credit Quality Indicator [Line Items]
Total	332		332		1
Consumer | 90 Days or More Past Due Loans | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	674		674		46
Consumer | Performing | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	19,442		19,442		47,084
Year two, fiscal year before current fiscal year	45,601		45,601		12,432
Year three, two years before current fiscal year	11,873		11,873		4,592
Year four, three years before current fiscal year	4,326		4,326		5,024
Year five, four years before current fiscal year	4,660		4,660		5,581
More than five years before current fiscal year	17,396		17,396		13,007
Revolving Loans Amortized Cost Basis	392,898		392,898		376,608
Revolving Loans Converted to Term Loans	38,391		38,391		38,570
Total	534,587		534,587		502,898
Consumer | Performing | Automobile
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	205,170		205,170		724,557
Year two, fiscal year before current fiscal year	633,269		633,269		525,017
Year three, two years before current fiscal year	437,528		437,528		204,578
Year four, three years before current fiscal year	161,245		161,245		166,103
Year five, four years before current fiscal year	123,616		123,616		80,012
More than five years before current fiscal year	71,682		71,682		45,415
Revolving Loans Amortized Cost Basis	0		0		0
Revolving Loans Converted to Term Loans	0		0		0
Total	1,632,510		1,632,510		1,745,682
Consumer | Performing | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	17,973		17,973		24,140
Year two, fiscal year before current fiscal year	20,979		20,979		10,144
Year three, two years before current fiscal year	(1,549)		(1,549)		8,206
Year four, three years before current fiscal year	3,729		3,729		7,435
Year five, four years before current fiscal year	8,720		8,720		7,406
More than five years before current fiscal year	12,707		12,707		15,736
Revolving Loans Amortized Cost Basis	1,189,191		1,189,191		991,737
Revolving Loans Converted to Term Loans	0		0		0
Total	1,251,750		1,251,750		1,064,804
Consumer | Non-Performing Loans | 90 Days or More Past Due Loans | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	0		0		0
Year two, fiscal year before current fiscal year	0		0		0
Year three, two years before current fiscal year	0		0		0
Year four, three years before current fiscal year	0		0		0
Year five, four years before current fiscal year	0		0		0
More than five years before current fiscal year	0		0		0
Revolving Loans Amortized Cost Basis	263		263		276
Revolving Loans Converted to Term Loans	643		643		710
Total	906		906		986
Consumer | Non-Performing Loans | 90 Days or More Past Due Loans | Automobile
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	47		47		38
Year two, fiscal year before current fiscal year	105		105		116
Year three, two years before current fiscal year	73		73		36
Year four, three years before current fiscal year	0		0		180
Year five, four years before current fiscal year	9		9		101
More than five years before current fiscal year	131		131		72
Revolving Loans Amortized Cost Basis	0		0		0
Revolving Loans Converted to Term Loans	0		0		0
Total	365		365		543
Consumer | Non-Performing Loans | 90 Days or More Past Due Loans | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	0		0		0
Year two, fiscal year before current fiscal year	0		0		0
Year three, two years before current fiscal year	0		0		0
Year four, three years before current fiscal year	0		0		0
Year five, four years before current fiscal year	0		0		0
More than five years before current fiscal year	38		38		38
Revolving Loans Amortized Cost Basis	594		594		1
Revolving Loans Converted to Term Loans	0		0		0
Total	$ 632		632		$ 39
Residential Mortgage and Consumer
Gross loan charge-offs
2023			11
2022			226
2021			206
2020			90
2019			428
Prior to 2019			953
Revolving Loans Amortized Cost Basis			103
Revolving Loans Converted to Term Loans			0
Total			$ 2,017