Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Interest Income (Expense), Operating		$ 1,201,145	$ 1,047,248	$ 1,039,573
Noninterest Income		286,400	(9,407)	63,182
Provision for Loan, Lease, and Other Losses		53,996	84,986	83,021
Interest Income (Expense), after Provision for Loan Loss		1,147,149	962,263	956,552
Labor and Related Expense		521,723	487,956	468,355
Information Technology and Data Processing		110,877	107,563	102,018
Occupancy, Net		55,011	54,622	57,204
Marketing and Advertising Expense		31,614	28,142	28,405
Equipment Expense		20,277	18,431	19,663
Professional Fees		23,934	21,601	19,911
Federal Deposit Insurance Corporation Premium Expense		36,713	38,439	67,072
Amortization of Intangible Assets		8,811	8,811	8,811
FHLB Advances, Prepayment Penalty	$ 14,000
Other Noninterest Expense		38,415	30,118	36,837
Noninterest Expense		855,639	818,397	813,682
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest		577,910	134,459	206,052
Income Tax Expense (Benefit)		103,133	11,314	23,097
Net Income (Loss)		474,777	123,145	182,956
Loans and Leases Receivable, Net of Deferred Income	29,768,586	31,163,614	29,768,586
Goodwill	1,104,992	1,104,992	1,104,992
Assets	43,023,068	45,202,596	43,023,068
Gain (Loss) on Sale of Mortgage Loans_narrative		(7,000)	(130,400)	(136,200)
Gain (Loss) on Sale of Investments			148,200	64,900
FDIC Special Assessment				30,600
Corporate and Commercial Specialty [Member]
Segment Reporting Information [Line Items]
A portion of total depreciation Technology expense		200	200	200
Community, Consumer and Business [Member]
Segment Reporting Information [Line Items]
A portion of total depreciation Occupancy expense		10,900	9,700	8,000
Risk Management and Shared Services [Member]
Segment Reporting Information [Line Items]
A portion of total depreciation Equipment expense		39,200	39,100	38,900
Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest Income (Expense), Operating		1,201,145	1,047,248	1,039,573
Net intersegment interest income (expense)		0	0	0
Segment net interest income		1,201,145	1,047,248	1,039,573
Noninterest Income		286,400	(9,407)	63,182
Interest income (expense) before provision		1,487,545	1,037,841	1,102,756
Provision for Loan, Lease, and Other Losses		53,996	84,986	83,021
Interest Income (Expense), after Provision for Loan Loss		1,433,549	952,855	1,019,734
Labor and Related Expense		521,723	487,956	468,355
Information Technology and Data Processing		110,877	107,563	102,018
Occupancy, Net		55,011	54,622	57,204
Marketing and Advertising Expense		31,614	28,142	28,405
Equipment Expense		20,277	18,431	19,663
Professional Fees		23,934	21,601	19,911
Payments of Financing Costs		8,264	8,471	5,408
Federal Deposit Insurance Corporation Premium Expense		36,713	38,439	67,072
Amortization of Intangible Assets		8,811	8,811	8,811
FHLB Advances, Prepayment Penalty			14,243
Other Noninterest Expense		38,415	30,118	36,837
Allocated indirect expense		0	0	0
Noninterest Expense		855,639	818,397	813,682
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest		577,910	134,459	206,052
Income Tax Expense (Benefit)		103,133	11,314	23,097
Net Income (Loss)		474,777	123,145	182,956
Loans and Leases Receivable, Net of Deferred Income	29,768,586	31,163,614	29,768,586	29,216,218
Goodwill	1,104,992	1,104,992	1,104,992	1,104,992
Assets	43,023,068	45,202,596	43,023,068	41,015,855
Operating Segments [Member] | Corporate and Commercial Specialty [Member]
Segment Reporting Information [Line Items]
Interest Income (Expense), Operating		960,032	976,878	933,929
Net intersegment interest income (expense)		(400,918)	(429,917)	(432,073)
Segment net interest income		559,114	546,961	501,856
Noninterest Income		61,925	53,435	51,905
Interest income (expense) before provision		621,039	600,396	553,761
Provision for Loan, Lease, and Other Losses		80,808	66,390	54,302
Interest Income (Expense), after Provision for Loan Loss		540,231	534,006	499,459
Labor and Related Expense		84,455	79,853	71,688
Information Technology and Data Processing		3,179	2,594	2,931
Occupancy, Net		81	0	0
Marketing and Advertising Expense		4,467	3,543	4,042
Equipment Expense		1	2	1
Professional Fees		1,015	825	1,359
Payments of Financing Costs		1,603	1,100	877
Federal Deposit Insurance Corporation Premium Expense		0	0	0
Amortization of Intangible Assets		0	0	0
FHLB Advances, Prepayment Penalty			0
Other Noninterest Expense		3,397	3,338	3,501
Allocated indirect expense		87,692	88,036	83,190
Noninterest Expense		185,890	179,291	167,589
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest		354,341	354,715	331,870
Income Tax Expense (Benefit)		68,165	64,346	59,143
Net Income (Loss)		286,176	290,369	272,727
Loans and Leases Receivable, Net of Deferred Income	16,959,921	18,129,783	16,959,921	16,045,897
Goodwill	525,836	525,836	525,836	525,836
Assets	17,794,372	18,910,235	17,794,372	16,897,021
Operating Segments [Member] | Community, Consumer and Business [Member]
Segment Reporting Information [Line Items]
Interest Income (Expense), Operating		266,645	247,791	309,291
Net intersegment interest income (expense)		538,345	579,587	487,897
Segment net interest income		804,990	827,378	797,188
Noninterest Income		209,451	198,485	193,948
Interest income (expense) before provision		1,014,441	1,025,863	991,136
Provision for Loan, Lease, and Other Losses		25,790	24,759	29,757
Interest Income (Expense), after Provision for Loan Loss		988,651	1,001,104	961,379
Labor and Related Expense		238,367	232,787	236,385
Information Technology and Data Processing		52,394	47,241	44,661
Occupancy, Net		109	61	95
Marketing and Advertising Expense		3,609	3,169	4,001
Equipment Expense		5,118	5,930	5,770
Professional Fees		2,347	1,978	1,933
Payments of Financing Costs		4,690	5,018	3,065
Federal Deposit Insurance Corporation Premium Expense		0	0	0
Amortization of Intangible Assets		0	0	0
FHLB Advances, Prepayment Penalty			0
Other Noninterest Expense		33,414	27,921	29,800
Allocated indirect expense		211,386	205,979	191,613
Noninterest Expense		551,434	530,084	517,323
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest		437,217	471,020	444,056
Income Tax Expense (Benefit)		91,816	97,460	91,770
Net Income (Loss)		345,401	373,560	352,286
Loans and Leases Receivable, Net of Deferred Income	12,318,648	12,618,662	12,318,648	12,642,123
Goodwill	579,156	579,156	579,156	579,156
Assets	13,892,891	13,476,698	13,892,891	13,453,475
Operating Segments [Member] | Risk Management and Shared Services [Member]
Segment Reporting Information [Line Items]
Interest Income (Expense), Operating		(25,532)	(177,421)	(203,647)
Net intersegment interest income (expense)		(137,427)	(149,670)	(55,824)
Segment net interest income		(162,959)	(327,091)	(259,471)
Noninterest Income		15,024	(261,327)	(182,671)
Interest income (expense) before provision		(147,935)	(588,418)	(442,142)
Provision for Loan, Lease, and Other Losses		(52,602)	(6,163)	(1,038)
Interest Income (Expense), after Provision for Loan Loss		(95,333)	(582,255)	(441,104)
Labor and Related Expense		198,901	175,316	160,282
Information Technology and Data Processing		55,304	57,728	54,426
Occupancy, Net		54,821	54,561	57,109
Marketing and Advertising Expense		23,538	21,430	20,362
Equipment Expense		15,158	12,499	13,892
Professional Fees		20,572	18,798	16,619
Payments of Financing Costs		1,971	2,353	1,466
Federal Deposit Insurance Corporation Premium Expense		36,713	38,439	67,072
Amortization of Intangible Assets		8,811	8,811	8,811
FHLB Advances, Prepayment Penalty			14,243
Other Noninterest Expense		1,604	(1,141)	3,534
Allocated indirect expense		(299,078)	(294,015)	(274,803)
Noninterest Expense		118,315	109,022	128,770
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest		(213,648)	(691,277)	(569,873)
Income Tax Expense (Benefit)		(56,848)	(150,492)	(127,816)
Net Income (Loss)		(156,800)	(540,785)	(442,057)
Loans and Leases Receivable, Net of Deferred Income	490,017	415,169	490,017	528,198
Goodwill	0	0	0	0
Assets	$ 11,335,805	$ 12,815,663	$ 11,335,805	$ 10,665,359