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Loans and Allowance for Credit Losses - Schedule of Company's Loan Portfolio as of the Dates Indicated (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unearned discounts and deferred fees, net	$ 18,589,790		$ 18,079,084
Allowance for loan losses	(232,113)	$ (224,310)	(228,952)	$ (156,146)	$ (149,190)	$ (148,993)
Unearned discounts and deferred fees, net	(274,667)		(300,730)
Loans after the allowance for loan losses and net unearned discounts and deferred fees	18,083,010		17,549,402
Financing receivable, accrued interest, before allowance for credit loss	67,300		66,700
Commercial and industrial \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unearned discounts and deferred fees, net	3,661,483		3,296,068
Allowance for loan losses	(54,110)	(46,490)	(41,090)	(28,916)	(28,863)	(26,959)
Commercial real estate \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unearned discounts and deferred fees, net	7,293,754		7,119,523
Allowance for loan losses	(105,090)	(106,634)	(116,175)	(69,079)	(64,629)	(65,475)
Commercial construction \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unearned discounts and deferred fees, net	472,329		494,842
Allowance for loan losses	(9,326)	(8,514)	(8,462)	(6,388)	(6,204)	(6,666)
Business banking \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unearned discounts and deferred fees, net	1,422,574		1,448,176
Allowance for loan losses	(20,685)	(20,315)	(19,899)	(16,748)	(14,631)	(14,913)
Residential real estate \| Residential Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unearned discounts and deferred fees, net	4,016,401		4,063,659
Allowance for loan losses	(31,481)	(31,096)	(32,291)	(25,829)	(25,935)	(25,954)
Consumer home equity \| Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unearned discounts and deferred fees, net	1,458,402		1,385,394
Allowance for loan losses	(7,080)	(6,891)	(7,472)	(5,781)	(5,684)	(5,595)
Other Consumer \| Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unearned discounts and deferred fees, net	264,847		271,422
Allowance for loan losses	$ (4,341)	$ (4,370)	$ (3,563)	$ (3,405)	$ (3,244)	$ (3,431)