Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract]
Net Income (Loss)	$ 474,777	$ 123,145	$ 182,956
Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract]
Provision for Loan, Lease, and Other Losses	53,996	84,986	83,021
Depreciation	50,356	48,845	46,989
Mortgage Servicing Rights (MSR) Impairment (Recovery)	1,441	(4,646)	(10,660)
Amortization of Intangible Assets	8,811	8,811	8,811
Accretion (Amortization) of Discounts and Premiums, Investments	42,969	44,857	38,508
Other Depreciation and Amortization	35,506	34,841	34,246
Marketable Securities, Gain (Loss)	0	144,326	64,864
Gain (Loss) on Disposition of Assets	(1,565)	1,042	(454)
(Gain) loss on mortgage banking activities, net	355	3,529	2,919
Gain (Loss) on Sale of Mortgage Loans	6,976	130,406	136,239
Increase (Decrease) in Obligation, Pension Benefits	(24,720)	(20,538)	(18,897)
Payments for Origination and Purchases of Loans Held-for-sale	(647,866)	(617,889)	(395,834)
Proceeds from Sale, Loan, Mortgage, Held-for-Sale	627,867	584,781	367,707
Increase (Decrease) in Other Operating Assets and Liabilities, Net [Abstract]
Increase (Decrease) in Accrued Interest Receivable, Net	6,654	1,797	(25,120)
Increase (Decrease) in Income Taxes	67,984	(36,748)	(77,849)
Increase (Decrease) in Interest Payable, Net	(18,906)	(960)	78,539
Increase (Decrease) in Other Accounts Payable and Accrued Liabilities	(1,061)	13,315	16,329
Increase (Decrease) in Derivative Assets and Liabilities	(60,372)	(1,127)	(93,916)
Increase (Decrease) in Other Noncurrent Assets	(17,195)	(13,477)	(9,231)
Increase (Decrease) in Other Operating Assets and Liabilities, Net	9,685	50,955	13,572
Net Cash Provided by (Used in) Operating Activities, Total	615,692	580,249	442,740
Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract]
Payments for (Proceeds from) Loans and Leases	(1,449,416)	(1,334,611)	(1,546,391)
Payment for Investing Activity [Abstract]
Payments to Acquire Debt Securities, Available-for-Sale	(1,960,264)	(3,315,219)	(1,936,635)
Payments to Acquire Held-to-Maturity Securities	(994)	0	(38,677)
Payments to Acquire Federal Home Loan Bank Stock	(235,232)	(154,413)	(146,308)
Proceeds from Investing Activity [Abstract]
Proceeds from Sale of Debt Securities, Available-for-sale	0	1,141,231	715,066
Proceeds from Sale of Federal Home Loan Bank Stock	159,955	226,758	202,451
Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale	1,189,948	1,159,775	397,675
Proceeds from Maturities, Prepayments and Calls of Held-to-Maturity Securities	140,373	123,748	143,001
Proceeds from Sale and Maturity of Other Investments	24,178	13,539	21,267
Proceeds from Sale of Mortgage Portfolio	564,375	0	844,362
Payments for (Proceeds from) Productive Assets	(36,374)	(44,987)	(61,813)
Net Change in Tax Credit Investments	(21,356)	(34,818)	(30,255)
Net Cash Provided by (Used in) Investing Activities, Total	(1,624,807)	(2,218,997)	(1,436,257)
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]
Increase (Decrease) in Deposits	904,174	1,202,385	3,809,948
Proceeds from (Repayments of) Short-Term Debt	(162,505)	143,589	(279,157)
Increase (Decrease) in Loans from Federal Home Loan Banks	1,605,250	510,000	(2,385,000)
Payments of FHLBank Borrowings, Financing Activities	(611,251)	(601,011)	(599)
Proceeds from FHLBank Borrowings, Financing Activities	413,822	2,656	1,369
Prepayment Fees on Advances, Net	0	(14,243)	0
Proceeds from Issuance of Long-term Debt	0	298,800	292,740
Proceeds from Issuance of Senior Long-Term Debt	(250,000)	0	0
Payments of Debt Issuance Costs	0	(936)	0
Finance Lease, Principal Payments	(295)	(88)	(86)
Proceeds from Issuance of Common Stock	0	331,023	0
Proceeds, Issuance of Shares, Share-Based Payment Arrangement, Including Option Exercised	6,887	37,576	4,297
Payments of Ordinary Dividends, Common Stock	(155,773)	(139,197)	(129,534)
Payments of Ordinary Dividends, Preferred Stock and Preference Stock	(11,500)	(11,500)	(11,500)
Proceeds from (Payment for) Other Financing Activity	(52)	0	0
Net Cash Provided by (Used in) Financing Activities, Total	1,709,732	1,734,529	1,295,885
Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation	700,617	95,781	302,368
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Beginning Balance	1,019,604	923,823	621,455
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending Balance	1,720,221	1,019,604	923,823
Supplemental Cash Flow Information [Abstract]
Interest Paid, Excluding Capitalized Interest, Operating Activity	988,322	1,075,196	838,828
Income Taxes Paid, Net	1,521	17,749	69,417
Real Estate Owned, Transfer to Real Estate Owned	26,225	15,827	9,841
Servicing Asset at Fair Value, Additions	8,716	6,707	3,564
Loan and Lease, Transfer from Held-in-Portfolio to Held-for-Sale	(56,046)	663,038	1,058,305
Equity Securities without Readily Determinable Fair Value, Upward Price Adjustment, Annual Amount	0	0	5,785
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax	14,162	(4,348)	(280)
Retained Earnings [Member]
Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract]
Net Income (Loss)	474,777	123,145	182,956
Other Liabilities [Member]
Supplemental Cash Flow Information [Abstract]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(12,222)	661	(5,084)
Other Assets [Member]
Supplemental Cash Flow Information [Abstract]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(1,332)	4,208	(1,757)
Performance/Service Based RSAs, RSA, [Member]
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]
Payments for Repurchase of Common Stock	(6,733)	(6,234)	(6,593)
Board Authorized Purchase Program [Member]
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]
Payments for Repurchase of Common Stock	$ (22,292)	$ (18,289)	$ 0