Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Cash Flow From Operating Activities
Net income	$ 86,824	$ 74,262	$ 91,007	$ 94,301	$ 161,086	$ 185,307
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Provision for credit losses	(2)		(35,004)		(3,992)	(58,009)
Depreciation and amortization					22,741	24,200
Change in MSRs valuation(a)					(19,400)	(10,239)
Amortization of other intangible assets	2,203		2,203		4,405	4,439
Amortization and accretion on earning assets, funding, and other, net					10,315	10,796
Net amortization of tax credit investments					17,072	16,552
Losses (gains) on sales of investment securities, net					(12)	16
Asset (gains), net					(1,865)	(4,796)
(Gains) on sale of branch, net					0	(1,038)
(Gain) loss on mortgage banking activities, net					3,036	(24,008)
Mortgage loans originated and acquired for sale					(403,951)	(889,315)
Proceeds from sales of mortgage loans held for sale					500,410	884,581
Changes in certain assets and liabilities
(Increase) decrease in interest receivable					(14,898)	8,466
(Decrease) increase in interest payable					1,501	(4,907)
(Decrease) increase in expense payable					(24,791)	11,274
Decrease in net derivative position					231,332	56,833
Net change in other assets and other liabilities					6,051	20,049
Net cash provided by operating activities					489,039	230,202
Cash Flow From Investing Activities
Net decrease (increase) in loans					(2,271,051)	478,170
Purchases of
AFS securities					(502,912)	(1,162,109)
HTM securities					(202,271)	(81,368)
Federal Home Loan Bank and Federal Reserve Bank stocks and equity securities					(69,339)	(1)
Premises, equipment, and software, net of disposals					(33,373)	(19,706)
Proceeds from
Sales of AFS and equity securities					1,069	158,743
Prepayments, calls, and maturities of AFS securities					296,179	699,584
Prepayments, calls, and maturities of HTM securities					111,796	195,107
Sales, prepayments, calls, and maturities of other assets					23,523	12,421
Net change in tax credit and alternative investments					(34,186)	(34,200)
Net cash provided by (used in) investing activities					(2,680,566)	249,056
Cash Flow From Financing Activities
Net increase in deposits					110,280	813,098
Net decrease in deposits due to branch sales					0	(31,083)
Net increase (decrease) in short-term funding					351,358	(26,112)
Net increase in short-term FHLB advances					2,045,000	0
Repayment of long-term FHLB advances					(408,870)	(18,049)
Proceeds from long-term FHLB advances					916	5,251
(Repayment) proceeds of finance lease principal					348	(1,035)
Proceeds from issuance of common stock for stock-based compensation plans					6,793	18,174
Payments for Repurchase of Redeemable Preferred Stock					0	65,000
Cash dividends on common stock					(60,914)	(55,693)
Cash dividends on preferred stock					(5,750)	(10,082)
Net cash provided by financing activities					2,033,084	577,074
Net increase (decrease) in cash and cash equivalents					(158,444)	1,056,332
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)	867,071		1,772,379		867,071	1,772,379	$ 1,025,515
Supplemental disclosures of cash flow information
Cash paid for interest					33,533	44,782
Cash (received from) income and franchise taxes					2,432	54,179
Loans and bank premises transferred to OREO					1,817	18,535
Capitalized mortgage servicing rights					5,231	7,488
Loans transferred from held for sale into portfolio, net					4,149	9,970
Transfer of AFS securities to HTM securities		1,600,000			1,621,990	0
Unsettled trades to purchase securities					1,450	0
Retained Earnings
Cash Flow From Operating Activities
Net income	$ 86,824	$ 74,262	$ 91,007	$ 94,301	161,086	185,307
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					(6,078)	(4,450)
Board Authorized Purchase Program [Member]
Cash Flow From Financing Activities
Purchase of treasury stock, open market purchases					$ 0	$ (47,945)