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Loans and Allowance for Credit Losses - Schedule of Composition of Loans and Impact of Adoption (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	$ 47,967,915		$ 47,967,915		$ 36,285,887
Allowance for credit losses on loans	(572,178)	$ (380,840)	(572,178)	$ (380,840)	(392,522)	$ (565,109)	$ (366,335)	$ (307,610)
Net loans	47,395,737		47,395,737		35,893,365
Taxable	731,633	561,428	1,905,907	1,594,411
Portfolio Segment Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	0		0		0
Net loans	0		0		0
Portfolio Segment After Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	47,967,915		47,967,915		36,285,887
Allowance for credit losses on loans	(572,178)		(572,178)		(392,522)
Net loans	47,395,737		47,395,737		35,893,365
Taxable			589,900		163,300
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	14,506,375		14,506,375		10,288,560
Allowance for credit losses on loans	(234,983)	(136,842)	(234,983)	(136,842)	(148,722)	(215,917)	(138,460)	(118,333)
Commercial \| Portfolio Segment Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	(219,588)		(219,588)		(232,301)
Commercial \| Portfolio Segment After Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	14,286,787		14,286,787		10,056,259
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	22,083,734		22,083,734		16,307,486
Allowance for credit losses on loans	(282,827)	(204,899)	(282,827)	(204,899)	(200,309)	(294,303)	(189,911)	(155,099)
Commercial real estate \| Portfolio Segment Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	(172,932)		(172,932)		(174,438)
Commercial real estate \| Portfolio Segment After Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	21,910,802		21,910,802		16,133,048
BBCC
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses on loans	(2,458)	(2,692)	(2,458)	(2,692)	(2,813)	(2,488)	(2,897)	(2,887)
BBCC \| Portfolio Segment Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	392,520		392,520		406,739
BBCC \| Portfolio Segment After Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	392,520		392,520		406,739
Residential real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	8,190,127		8,190,127		6,797,586
Allowance for credit losses on loans	(31,431)	(21,488)	(31,431)	(21,488)	(22,922)	(31,850)	(23,135)	(20,837)
Residential real estate \| Portfolio Segment Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	0		0		0
Residential real estate \| Portfolio Segment After Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	8,190,127		8,190,127		6,797,586
Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	3,187,679		3,187,679		2,892,255
Consumer \| Portfolio Segment Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	(3,187,679)		(3,187,679)		(2,892,255)
Indirect
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	1,058,734		1,058,734		1,096,778
Allowance for credit losses on loans	(7,961)	(5,661)	(7,961)	(5,661)	(8,434)	(8,430)	(1,233)	(1,236)
Indirect \| Portfolio Segment Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	1,058,734		1,058,734		1,096,778
Indirect \| Portfolio Segment After Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	1,058,734		1,058,734		1,096,778
Direct
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	589,133		589,133		514,144
Allowance for credit losses on loans	(2,418)	(2,427)	(2,418)	(2,427)	(2,304)	(2,564)	(3,131)	(3,169)
Direct \| Portfolio Segment Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	589,133		589,133		514,144
Direct \| Portfolio Segment After Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	589,133		589,133		514,144
Home equity
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	1,539,812		1,539,812		1,281,333
Allowance for credit losses on loans	(10,100)	$ (6,831)	(10,100)	$ (6,831)	(7,018)	$ (9,557)	$ (7,568)	$ (6,049)
Home equity \| Portfolio Segment Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	1,539,812		1,539,812		1,281,333
Home equity \| Portfolio Segment After Reclassifications
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	1,539,812		1,539,812		1,281,333
Direct Finance Leases
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans, net of unearned income	$ 84,900		$ 84,900		$ 120,600