Allowance for Credit Losses - Age Analysis of Past Due Loans Segregated by Class of Loans (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) loan	Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($)
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	$ 7,183,969	$ 6,999,990
Nonaccrual	$ 19,052	$ 66,291	$ 146,774
Number of modified loans | loan	0	8
CARES Act, Paycheck Protection Program Loans
Financing Receivable, Past Due [Line Items]
Number of modified loans | loan		8
Modified loans		$ 28,800
Current
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	$ 7,144,576	6,927,943
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	18,093	3,085
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	2,248	2,672
Total Past Due Loans
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	39,393	72,048
Commercial | CARES Act, Paycheck Protection Program Loans
Financing Receivable, Past Due [Line Items]
Modified loans		28,800
Commercial | Commercial real estate
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	2,538,839	2,690,528
Nonaccrual	7,100	31,488	101,070
Commercial | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	1,510,392	1,513,523
Nonaccrual	283	15,239	16,985
Commercial | Commercial construction
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	381,963	424,755
Nonaccrual	384	2,471	384
Commercial | Business banking
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	1,205,944	1,135,693
Nonaccrual	4,490	9,641	17,122
Commercial | Current | Commercial real estate
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	2,523,315	2,659,040
Commercial | Current | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	1,505,805	1,497,755
Commercial | Current | Commercial construction
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	381,579	421,834
Commercial | Current | Business banking
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	1,199,586	1,124,748
Commercial | 30-59 Days Past Due | Commercial real estate
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	8,424	0
Commercial | 30-59 Days Past Due | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	4,304	529
Commercial | 30-59 Days Past Due | Commercial construction
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	0	450
Commercial | 30-59 Days Past Due | Business banking
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	1,583	813
Commercial | 60-89 Days Past Due | Commercial real estate
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	0	0
Commercial | 60-89 Days Past Due | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	0	0
Commercial | 60-89 Days Past Due | Commercial construction
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	0	0
Commercial | 60-89 Days Past Due | Business banking
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	285	491
Commercial | Total Past Due Loans | Commercial real estate
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	15,524	31,488
Commercial | Total Past Due Loans | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	4,587	15,768
Commercial | Total Past Due Loans | Commercial construction
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	384	2,921
Commercial | Total Past Due Loans | Business banking
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	6,358	10,945
Consumer | Consumer real estate
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	1,421,953	1,127,585
Nonaccrual	6,526	7,294	11,117
Consumer | Other consumer
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	124,878	107,906
Nonaccrual	269	158	$ 96
Consumer | Current | Consumer real estate
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	1,409,907	1,117,073
Consumer | Current | Other consumer
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	124,384	107,492
Consumer | 30-59 Days Past Due | Consumer real estate
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	3,617	1,087
Consumer | 30-59 Days Past Due | Other consumer
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	165	206
Consumer | 60-89 Days Past Due | Consumer real estate
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	1,903	2,130
Consumer | 60-89 Days Past Due | Other consumer
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	60	50
Consumer | Total Past Due Loans | Consumer real estate
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	12,046	10,512
Consumer | Total Past Due Loans | Other consumer
Financing Receivable, Past Due [Line Items]
Portfolio loans, net of unearned income	$ 494	$ 414