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Loans - Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Jun. 30, 2025	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 92,426	$ 100,865	$ 91,060	$ 91,060	$ 96,868	$ 96,868
Charge-offs	32,206	11,226		40,754	21,615
Recoveries	823	1,706		4,343	6,567
Provision	35,216	4,644		41,610	14,169
Ending balance	96,259	95,989	92,426	96,259	95,989	91,060
Average balance	$ 7,523,624	$ 7,930,996		$ 7,564,411	$ 7,872,235
Net charge-offs to loan average balance (annualized)	1.65%	0.48%		0.64%	0.26%
Provision for credit losses	$ 36,800	$ 4,600		$ 43,100	$ 12,800
Provision (release) for loan credit losses	35,216	4,644		41,610	14,169
Provision (benefit) for off-balance sheet commitments	1,600	(36)		1,500	(1,300)
Provision (benefit) for held to maturity securities	(4)	(5)		(7)	(11)
Real estate | Commercial Real Estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	16,785	17,244	16,546	16,546	19,625	19,625
Charge-offs	0	0		728	480	480
Recoveries	5	21		18	318
Provision	1,386	(435)		2,340	(2,633)
Ending balance	18,176	16,830	16,785	18,176	16,830	16,546
Average balance	$ 2,450,148	$ 2,507,566		$ 2,435,301	$ 2,481,274
Net charge-offs to loan average balance (annualized)	0.00%	0.00%		0.04%	0.01%
Provision (release) for loan credit losses	$ 1,386	$ (435)		$ 2,340	$ (2,633)
Real estate | Construction/ Land/ Land Development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	6,324	9,274	7,398	7,398	9,990	9,990
Charge-offs	0	0		0	0	0
Recoveries	0	0		0	0
Provision	1,417	(546)		343	(1,262)
Ending balance	7,741	8,728	6,324	7,741	8,728	7,398
Average balance	$ 644,455	$ 1,019,302		$ 734,621	$ 1,069,360
Net charge-offs to loan average balance (annualized)	0.00%	0.00%		0.00%	0.00%
Provision (release) for loan credit losses	$ 1,417	$ (546)		$ 343	$ (1,262)
Real estate | Residential Real Estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	13,639	11,780	12,454	12,454	10,619	10,619
Charge-offs	0	11		119	11	11
Recoveries	3	4		56	12
Provision	722	302		1,973	1,455
Ending balance	14,364	12,075	13,639	14,364	12,075	12,454
Average balance	$ 1,992,766	$ 1,824,725		$ 1,953,007	$ 1,784,035
Net charge-offs to loan average balance (annualized)	0.00%	0.00%		0.00%	0.00%
Provision (release) for loan credit losses	$ 722	$ 302		$ 1,973	$ 1,455
Commercial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	54,175	61,184	53,449	53,449	55,330	55,330
Charge-offs	32,184	11,195		39,740	21,044	22,787
Recoveries	812	1,680		4,244	6,228
Provision	31,679	5,070		36,529	16,225
Ending balance	54,482	56,739	54,175	54,482	56,739	53,449
Average balance	$ 1,994,755	$ 2,071,984		$ 2,022,286	$ 2,107,195
Net charge-offs to loan average balance (annualized)	6.24%	1.83%		2.35%	0.94%
Provision (release) for loan credit losses	$ 31,679	$ 5,070		$ 36,529	$ 16,225
Mortgage Warehouse Lines of Credit
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	780	676	501	501	529	529
Charge-offs	0	0		0	0	0
Recoveries	0	0		0	0
Provision	47	(13)		326	134
Ending balance	827	663	780	827	663	501
Average balance	$ 420,848	$ 484,680		$ 397,466	$ 407,553
Net charge-offs to loan average balance (annualized)	0.00%	0.00%		0.00%	0.00%
Provision (release) for loan credit losses	$ 47	$ (13)		$ 326	$ 134
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	723	707	712	712	775	775
Charge-offs	22	20		167	80	362
Recoveries	3	1		25	9
Provision	(35)	266		99	250
Ending balance	669	954	$ 723	669	954	$ 712
Average balance	$ 20,652	$ 22,739		$ 21,730	$ 22,818
Net charge-offs to loan average balance (annualized)	0.37%	0.33%		0.87%	0.42%
Provision (release) for loan credit losses	$ (35)	$ 266		$ 99	$ 250

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Percentage of writeoff after recovery to average financing receivables outstanding.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
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Amount, excluding accrued interest, of credit loss expense (reversal of expense) on investment in debt security measured at amortized cost (held-to-maturity).

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Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

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Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease.

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Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

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Average amount outstanding, before allowance for credit loss, of financing receivables.

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Amount of expense (reversal of expense) for expected credit loss for off-balance sheet credit exposure. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging.

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