Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Cash Flow From Operating Activities
Net income	$ 96,275	$ 74,262	$ 88,809	$ 94,301	$ 257,360	$ 274,117
Adjustments to reconcile net income to net cash provided by operating activities
Provision for credit losses	16,998		(24,010)		13,006	(82,018)
Depreciation and amortization					33,743	36,109
Change in MSRs valuation(a)					(22,348)	(12,231)
Amortization of other intangible assets	2,203		2,203		6,608	6,642
Amortization and accretion on earning assets, funding, and other, net					13,280	12,184
Net amortization of tax credit investments					25,916	25,196
Losses (gains) on sales of investment securities, net					(260)	16
Asset (gains), net	(18)		(5,228)		(1,883)	(10,024)
(Gains) on sale of branches, net	0		0		0	(1,038)
(Gain) loss on mortgage banking activities, net					5,712	(32,304)
Mortgage loans originated and acquired for sale					(535,694)	(1,345,158)
Proceeds from sales of mortgage loans held for sale					619,940	1,348,006
Changes in certain assets and liabilities
(Increase) decrease in interest receivable					(35,254)	11,252
(Decrease) increase in interest payable					1,795	(13,287)
(Decrease) increase in expense payable					(17,994)	24,509
Decrease in net derivative position					320,972	82,122
Net change in other assets and other liabilities					37,430	40,049
Net cash provided by operating activities					722,330	364,141
Cash Flow From Investing Activities
Net decrease (increase) in loans					(3,595,331)	804,497
Purchases of
AFS securities					(511,401)	(1,985,700)
HTM securities					(245,826)	(250,259)
Federal Home Loan Bank and Federal Reserve Bank stocks and equity securities					(111,057)	(9)
Premises, equipment, and software, net of disposals					(45,441)	(34,337)
Proceeds from
Sales of AFS and equity securities					1,320	158,743
Prepayments, calls, and maturities of AFS securities					392,275	927,053
Prepayments, calls, and maturities of HTM securities					153,163	243,063
Sales, prepayments, calls, and maturities of other assets					31,732	18,149
Net change in tax credit and alternative investments					(50,386)	(45,655)
Net cash (used in) investing activities					(3,980,951)	(162,040)
Cash Flow From Financing Activities
Net increase in deposits					732,347	1,400,162
Net decrease in deposits due to branch sales					0	(31,083)
Net increase (decrease) in short-term funding					(69,902)	70,179
Net increase in short-term FHLB advances					2,583,000	0
Repayment of long-term FHLB advances					(414,004)	(18,276)
Proceeds from long-term FHLB advances					1,838	6,576
(Repayment) proceeds of finance lease principal					327	(1,056)
Repayments of Senior Debt					0	(300,000)
Proceeds from issuance of common stock for stock-based compensation plans					8,059	18,629
Payments for Repurchase of Redeemable Preferred Stock					0	164,458
Cash dividends on common stock					(91,256)	(86,238)
Cash dividends on preferred stock					(8,625)	(14,236)
Net cash provided by financing activities					2,735,525	767,695
Net increase (decrease) in cash and cash equivalents					(523,096)	969,796
Cash and cash equivalents at beginning of period		1,025,515		716,048	1,025,515	716,048	$ 716,048
Cash and cash equivalents at end of period(b)	502,419		1,685,843		502,419	1,685,843	$ 1,025,515
Supplemental disclosures of cash flow information
Cash paid for interest					83,337	69,470
Cash paid for income and franchise taxes					6,087	56,262
Loans and bank premises transferred to OREO					5,052	33,794
Capitalized mortgage servicing rights					6,316	11,761
Loans transferred from held for sale into portfolio, net					1,789	10,071
Transfer of AFS securities to HTM securities		1,600,000			1,621,990	0
Unsettled trades to purchase securities					4,130	9,855
Gain on sale and net write-up of equity securities					5,690	0
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge					14,703	0
Retained Earnings
Cash Flow From Operating Activities
Net income	$ 96,275	$ 74,262	$ 88,809	$ 94,301	257,360	274,117
ABRC
Proceeds from
Sales, prepayments, calls, and maturities of other assets					0	2,415
Performance/Service Based RSAs, RSA,
Cash Flow From Financing Activities
Purchase of treasury stock, open market purchases					(6,259)	(4,562)
Board Authorized Purchase Program [Member]
Cash Flow From Financing Activities
Purchase of treasury stock, open market purchases					$ 0	$ (107,943)