Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Cash flows from operating activities
Net income	$ 87,154	$ 103,360	$ 86,824	$ 74,262	$ 190,514	$ 161,086
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	22,100		(2)		40,071	(3,992)
Depreciation and amortization					22,914	22,741
Change in MSRs valuation					(5,135)	(19,400)
Amortization of other intangible assets	2,203		2,203		4,405	4,405
Amortization and accretion on earning assets, funding, and other, net					16,509	10,315
Net amortization of tax credit investments					17,227	17,072
(Gains) on sales of investment securities, net					0	(12)
Asset losses (gains), net	299		(1,677)		35	(1,865)
Loss on mortgage banking activities, net					1,389	3,036
Mortgage loans originated and acquired for sale					(168,395)	(403,951)
Proceeds from sales of mortgage loans held for sale					151,167	500,410
Changes in certain assets and liabilities:
(Increase) in interest receivable					(14,736)	(14,898)
Increase in interest payable					44,367	1,501
(Decrease) in expense payable					(40,882)	(24,791)
(Decrease) increase in net derivative position					(37,175)	231,332
Net change in other assets and other liabilities					(43,503)	6,051
Net cash provided by operating activities					178,771	489,039
Cash flows from investing activities
Net (increase) in loans					(1,054,924)	(2,271,051)
Purchases of:
AFS securities					(948,326)	(502,012)
HTM securities					(41,524)	(202,271)
Federal Home Loan Bank and Federal Reserve Bank stocks and equity securities					(97,622)	(70,239)
Proceeds from:
Sales of AFS securities					0	1,061
Sale of Federal Home Loan Bank and Federal Reserve Bank stocks and equity securities					115,975	8
Prepayments, calls, and maturities of AFS securities					172,680	296,179
Prepayments, calls, and maturities of HTM securities					62,212	111,796
Sales, prepayments, calls, and maturities of other assets					17,988	23,523
Premises, equipment, and software, net of disposals					(29,663)	(33,373)
Net change in tax credit and alternative investments					(14,116)	(34,186)
Net cash (used in) investing activities					(1,817,320)	(2,680,566)
Cash flows from financing activities
Net increase in deposits					2,378,308	110,280
Net increase (decrease) in short-term funding					(264,684)	351,358
Net increase (decrease) in short-term FHLB advances					(685,000)	2,045,000
Repayment of long-term FHLB advances					(537)	(408,870)
Proceeds from long-term FHLB advances					115	916
Proceeds from issuance of long-term funding					292,740	0
(Repayment) proceeds of finance lease principal					(43)	348
Proceeds from issuance of common stock for stock-based compensation plans					1,859	6,793
Cash dividends on common stock					(64,009)	(60,914)
Cash dividends on preferred stock					(5,750)	(5,750)
Net cash provided by financing activities					1,646,755	2,033,084
Net increase (decrease) in cash and cash equivalents					8,207	(158,444)
Cash and cash equivalents at beginning of period		621,455		1,025,515	621,455	1,025,515	$ 1,025,515
Cash and cash equivalents at end of period(a)	629,662		867,071		629,662	867,071	621,455
Supplemental disclosures of cash flow information
Cash paid for interest					347,202	33,533
Cash paid for income and franchise taxes					58,985	2,432
Loans and bank premises transferred to OREO					3,632	1,817
Capitalized mortgage servicing rights					1,322	5,231	$ 7,279
Loans transferred into (from) held for sale from (into) portfolio, net					(840)	4,149
Transfer of AFS securities to HTM securities					0	1,621,990
Unsettled trades to purchase securities					0	1,450
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge					9,651	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	(22,961)		0		(12,630)	0
Performance/Service Based RSAs, RSA,
Cash flows from financing activities
Purchase of treasury stock, open market purchases					(6,246)	(6,078)
Retained Earnings [Member]
Cash flows from operating activities
Net income	$ 87,154	$ 103,360	$ 86,824	$ 74,262	$ 190,514	$ 161,086