Allowance for Credit Losses and Credit Quality Information - Summary of Nonaccrual and Past Due Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	$ 7,882,055	$ 9,014,677	$ 8,464,562
Nonaccrual Loans	$ 16,609	$ 41,908
Percent past due	0.50%	0.50%
Percent of accruing current balances	99.29%	99.04%
Percent of nonaccrual loans	0.21%	0.46%
% of Total Loans	100.00%	100.00%
Nonaccrual with an allowance (prior year less than)	$ 100	$ 100
Reverse mortgage, fair value	3,900	10,100	16,600
30–89 Days Past Due and Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	$ 29,289	$ 28,152
Percent past due	0.37%	0.31%
Greater Than 90 Days Past Due and Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	$ 9,991	$ 16,694
Percent past due	0.13%	0.19%
Total Past Due And Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	$ 39,280	$ 44,846
Accruing Current Balances
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	7,826,166	8,927,923
Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	542,733	764,393	999,879
Nonaccrual Loans	3,125	3,247
Residential | 30–89 Days Past Due and Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,856	3,049
Residential | Greater Than 90 Days Past Due and Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	0	25
Residential | Total Past Due And Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,856	3,074
Residential | Accruing Current Balances
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	537,752	758,072
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,158,573	1,165,917	1,128,731
Nonaccrual Loans	2,380	2,310
Consumer | 30–89 Days Past Due and Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	10,227	8,355
Consumer | Greater Than 90 Days Past Due and Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	8,634	11,035
Consumer | Total Past Due And Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	18,861	19,390
Consumer | Accruing Current Balances
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,137,332	1,144,217
Commercial and industrial | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	2,270,319	2,949,303	2,235,428
Nonaccrual Loans	8,211	13,816
Commercial and industrial | Commercial | 30–89 Days Past Due and Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	5,007	7,313
Commercial and industrial | Commercial | Greater Than 90 Days Past Due and Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	547	3,652
Commercial and industrial | Commercial | Total Past Due And Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	5,554	10,965
Commercial and industrial | Commercial | Accruing Current Balances
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	2,256,554	2,924,522
Owner-occupied commercial | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,341,707	1,332,727	1,296,466
Nonaccrual Loans	811	5,360
Owner-occupied commercial | Commercial | 30–89 Days Past Due and Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	741	3,120
Owner-occupied commercial | Commercial | Greater Than 90 Days Past Due and Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	0	892
Owner-occupied commercial | Commercial | Total Past Due And Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	741	4,012
Owner-occupied commercial | Commercial | Accruing Current Balances
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,340,155	1,323,355
Commercial mortgages | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,881,510	2,086,062	2,222,976
Nonaccrual Loans	2,070	17,175
Commercial mortgages | Commercial | 30–89 Days Past Due and Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	3,525	5,944
Commercial mortgages | Commercial | Greater Than 90 Days Past Due and Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	810	1,090
Commercial mortgages | Commercial | Total Past Due And Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	4,335	7,034
Commercial mortgages | Commercial | Accruing Current Balances
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,875,105	2,061,853
Construction | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	687,213	716,275	$ 581,082
Nonaccrual Loans	12	0
Construction | Commercial | 30–89 Days Past Due and Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	7,933	371
Construction | Commercial | Greater Than 90 Days Past Due and Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	0	0
Construction | Commercial | Total Past Due And Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	7,933	371
Construction | Commercial | Accruing Current Balances
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	679,268	715,904
Student loans | Consumer | Total Past Due And Still Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	$ 17,000	$ 18,200