Loans and Allowance for Credit Losses - Schedule of Financing Receivable, Past Due (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Past Due [Line Items]
Total	$ 14,055,800	$ 13,948,360
Total Past Due
Financing Receivable, Past Due [Line Items]
Total	44,770	57,130
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	20,861	30,936
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	7,097	9,370
90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total	16,812	16,824
Current
Financing Receivable, Past Due [Line Items]
Total	14,011,030	13,891,230
Commercial and industrial | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	3,070,740	3,019,631
Commercial and industrial | Total Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	765	3,781
Commercial and industrial | 30-59 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	300	3,316
Commercial and industrial | 60-89 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	0	0
Commercial and industrial | 90 or More Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	465	465
Commercial and industrial | Current | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	3,069,975	3,015,850
Commercial real estate | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	5,516,380	5,453,847
Commercial real estate | Total Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	0	0
Commercial real estate | 30-59 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	0	0
Commercial real estate | 60-89 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	0	0
Commercial real estate | 90 or More Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	0	0
Commercial real estate | Current | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	5,516,380	5,453,847
Commercial construction | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	386,232	384,637
Commercial construction | Total Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	0	0
Commercial construction | 30-59 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	0	0
Commercial construction | 60-89 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	0	0
Commercial construction | 90 or More Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	0	0
Commercial construction | Current | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	386,232	384,637
Business banking | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	1,103,884	1,089,593
Business banking | Total Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	7,167	6,304
Business banking | 30-59 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	3,788	3,455
Business banking | 60-89 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	1,083	1,647
Business banking | 90 or More Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	2,296	1,202
Business banking | Current | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	1,096,717	1,083,289
Residential real estate | Residential Real Estate
Financing Receivable, Past Due [Line Items]
Total	2,560,241	2,582,465
Residential real estate | Total Past Due | Residential Real Estate
Financing Receivable, Past Due [Line Items]
Total	21,500	28,768
Residential real estate | 30-59 Days Past Due | Residential Real Estate
Financing Receivable, Past Due [Line Items]
Total	11,964	17,116
Residential real estate | 60-89 Days Past Due | Residential Real Estate
Financing Receivable, Past Due [Line Items]
Total	4,522	4,888
Residential real estate | 90 or More Days Past Due | Residential Real Estate
Financing Receivable, Past Due [Line Items]
Total	5,014	6,764
Residential real estate | Current | Residential Real Estate
Financing Receivable, Past Due [Line Items]
Total	2,538,741	2,553,697
Consumer home equity | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	1,219,922	1,211,168
Consumer home equity | Total Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	14,547	17,321
Consumer home equity | 30-59 Days Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	4,411	6,517
Consumer home equity | 60-89 Days Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	1,321	2,600
Consumer home equity | 90 or More Days Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	8,815	8,204
Consumer home equity | Current | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	1,205,375	1,193,847
Other Consumer | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	198,401	207,019
Other Consumer | Total Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	791	956
Other Consumer | 30-59 Days Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	398	532
Other Consumer | 60-89 Days Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	171	235
Other Consumer | 90 or More Days Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	222	189
Other Consumer | Current | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total	$ 197,610	$ 206,063