Consolidated Balance Sheets - USD ($)	Mar. 31, 2026	Dec. 31, 2025
Assets [Abstract]
Cash and Due from Banks	$ 465,318,000	$ 574,698,000
Interest-Bearing Deposits in Banks and Other Financial Institutions	920,684,000	1,144,123,000
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure	175,000	1,400,000
Debt Securities, Available-for-Sale	5,514,456,000	5,397,563,000
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	3,570,843,000	3,602,519,000
Equity Securities, FV-NI and without Readily Determinable Fair Value	26,109,000	26,060,000
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	290,189,000	252,514,000
Loans and Leases Receivable, Net of Deferred Income	31,798,164,000	31,163,614,000
Loans and Leases Receivable, Allowance	(385,756,000)	(378,068,000)
Loans and Leases Receivable, Net Amount	31,412,408,000	30,785,546,000
Other Short-Term Investments	230,954,000	236,657,000
Property, Plant and Equipment, Net	376,760,000	381,624,000
Life Insurance, Corporate or Bank Owned, Amount	694,765,000	694,452,000
Goodwill	1,104,992,000	1,104,992,000
Intangible Assets, Net (Excluding Goodwill)	20,647,000	22,849,000
Servicing Asset at Fair Value, Amount	87,599,000	86,337,000
Interest Receivable	161,021,000	161,118,000
Other Assets	629,359,000	657,645,000
Assets, Total	45,593,740,000	45,202,596,000
Liabilities and Equity [Abstract]
Noninterest-Bearing Domestic Deposit, Demand	6,125,067,000	6,126,632,000
Interest-Bearing Deposit Liabilities, Domestic	29,606,698,000	29,425,976,000
Deposits, Total	35,731,765,000	35,552,608,000
Short-Term Debt	395,652,000	307,864,000
Federal Home Loan Bank, Advance, Branch of FHLBank, Amount	3,421,762,000	3,268,094,000
Other Long-Term Debt	592,629,000	594,276,000
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount	39,276,000	41,276,000
Other Liabilities	414,784,000	463,131,000
Liabilities, Total	40,595,868,000	40,227,249,000
Equity, Attributable to Parent [Abstract]
Preferred Stock, Including Additional Paid in Capital	194,112,000	194,112,000
Common Stock, Value, Issued	1,890,000	1,890,000
Additional Paid in Capital, Common Stock	2,052,504,000	2,050,410,000
Retained Earnings (Accumulated Deficit)	3,303,458,000	3,226,756,000
Accumulated Other Comprehensive Income (Loss), Net of Tax	(44,505,000)	(7,566,000)
Treasury Stock, Value	(509,587,000)	(490,255,000)
Total Common Equity	4,803,760,000	4,781,235,000
Equity, Attributable to Parent, Total	4,997,872,000	4,975,347,000
Liabilities and Equity, Total	$ 45,593,740,000	$ 45,202,596,000
Preferred Stock, Shares Authorized	750,000	750,000
Preferred Stock, Shares Issued	200,000	200,000
Common Stock, Shares Authorized	250,000,000	250,000,000
Common Stock, Shares, Issued	189,016,409	189,016,409
Common Stock, Shares, Outstanding	165,438,367	165,979,940
Preferred Stock, Par or Stated Value Per Share	$ 1.00	$ 1.00
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Residential Mortgage [Member]
Assets [Abstract]
Financing Receivable, Held-for-Sale	$ 87,461,000	$ 72,499,000
Loans and Leases Receivable, Net of Deferred Income	6,727,734,000	6,793,957,000
Liabilities and Equity [Abstract]
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount	$ 200,000	$ 300,000