Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net Income (Loss)		$ 123,145	$ 182,956	$ 366,122
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Provision for Loan, Lease, and Other Losses		84,986	83,021	32,998
Depreciation		48,845	46,989	45,088
Mortgage Servicing Rights (MSR) Impairment (Recovery)		(4,646)	(10,660)	(22,264)
Amortization of Intangible Assets		8,811	8,811	8,811
Accretion (Amortization) of Discounts and Premiums, Investments		44,857	38,508	14,980
Other Depreciation and Amortization		34,841	34,246	34,684
Marketable Securities, Gain (Loss)		144,326	64,864	1,674
Gain (Loss) on Disposition of Assets	[1]	1,042	(454)	(1,338)
(Gain) loss on mortgage banking activities, net		3,529	2,919	3,654
Gain (Loss) on Sale of Mortgage Loans		130,406	136,239	0
Payments for Origination and Purchases of Loans Held-for-sale		(617,889)	(395,834)	(600,114)
Proceeds from Sale, Loan, Mortgage, Held-for-Sale		584,781	367,707	715,035
Increase (Decrease) in Other Operating Assets and Liabilities, Net [Abstract]
Increase (Decrease) in Accrued Interest Receivable, Net		1,797	(25,120)	(63,921)
Increase (Decrease) in Income Taxes		(36,748)	(77,849)	40,611
Increase (Decrease) in Interest Payable, Net		(960)	78,539	12,608
Increase (Decrease) in Other Accounts Payable and Accrued Liabilities		13,315	16,329	(5,297)
Increase (Decrease) in Derivative Assets and Liabilities		(1,127)	(93,916)	269,774
Increase (Decrease) in Other Operating Assets and Liabilities, Net		16,940	(14,556)	(6,539)
Net Cash Provided by (Used in) Operating Activities, Total		580,249	442,740	846,566
Net Cash Provided by (Used in) Investing Activities [Abstract]
Payments for (Proceeds from) Loans and Leases		(1,334,611)	(1,546,391)	(4,579,431)
Payments for Investing Activities [Abstract]
Payments to Acquire Debt Securities, Available-for-Sale		(3,315,219)	(1,936,635)	(959,977)
Payments to Acquire Held-to-Maturity Securities		0	(38,677)	(301,052)
Payments to Acquire Federal Home Loan Bank Stock		(154,413)	(146,308)	(128,620)
Proceeds from Investing Activities [Abstract]
Proceeds from Sale of Debt Securities, Available-for-sale		1,141,231	715,066	110,177
Proceeds from Sale of Other Investments		226,758	202,451	528
Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale		1,159,775	397,675	494,197
Proceeds from Maturities, Prepayments and Calls of Held-to-Maturity Securities		123,748	143,001	196,605
Proceeds from Maturities, Prepayments and Calls of Other Investments		13,539	21,267	33,795
Proceeds from Sale of Mortgage Portfolio		0	844,362	0
Payments for (Proceeds from) Productive Assets		(44,987)	(61,813)	(62,711)
Net Change in Tax Credit Investments		(34,818)	(30,255)	(58,323)
Net Cash Provided by (Used in) Investing Activities, Total		(2,218,997)	(1,436,257)	(5,254,811)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Increase (Decrease) in Deposits		1,202,385	3,809,948	1,169,983
Proceeds from (Repayments of) Short-Term Debt		143,589	(279,157)	251,674
Increase (Decrease) in Loans from Federal Home Loan Banks		510,000	(2,385,000)	3,125,000
Payments of FHLBank Borrowings, Financing Activities		(601,011)	(599)	(413,558)
Proceeds from FHLBank Borrowings, Financing Activities		2,656	1,369	1,775
Prepayment Fees on Advances, Net		(14,243)	0	0
Proceeds from Issuance of Long-term Debt		298,800	292,740	0
Payments of Debt Issuance Costs		(936)	0	0
Finance Lease, Principal Payments		(88)	(86)	306
Proceeds from Issuance of Common Stock		331,023	0	0
Proceeds, Issuance of Shares, Share-Based Payment Arrangement, Including Option Exercised		37,576	4,297	11,061
Payments of Ordinary Dividends, Common Stock		(139,197)	(129,534)	(123,137)
Payments of Ordinary Dividends, Preferred Stock and Preference Stock		(11,500)	(11,500)	(11,500)
payments for repurchase of common stock for tax withholding		0	0	(938)
Net Cash Provided by (Used in) Financing Activities, Total		1,734,529	1,295,885	4,004,185
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total		95,781	302,368	(404,060)
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Beginning Balance		923,823	621,455	1,025,515
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending Balance		1,019,604	923,823	621,455
Supplemental Cash Flow Information [Abstract]
Interest Paid, Excluding Capitalized Interest, Operating Activities		1,075,196	838,828	174,675
Income Taxes Paid, Net		17,749	69,417	18,395
Real Estate Owned, Transfer to Real Estate Owned		15,827	9,841	5,591
Servicing Asset at Fair Value, Additions		6,707	3,564	7,279
Loan and Lease, Transfer from Held-in-Portfolio to Held-for-Sale		663,038	1,058,305	18
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Transfer, Amount		0	0	1,621,990
Equity Securities without Readily Determinable Fair Value, Upward Price Adjustment, Annual Amount		0	5,785	5,690
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax		(4,348)	(280)	3,360
Other Liabilities [Member]
Supplemental Cash Flow Information [Abstract]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge		661	(5,084)	16,163
Other Assets [Member]
Supplemental Cash Flow Information [Abstract]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge		4,208	(1,757)	1,405
Performance/Service Based RSAs, RSA, [Member]
Net Cash Provided by (Used in) Financing Activities [Abstract]
Payments for Repurchase of Common Stock		(6,234)	(6,593)	(6,480)
Board Authorized Purchase Program [Member]
Net Cash Provided by (Used in) Financing Activities [Abstract]
Payments for Repurchase of Common Stock		$ (18,289)	$ 0	$ 0

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