Consolidated Balance Sheets - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Assets
Cash and due from banks	$ 386,879	$ 453,432
Money market and other interest-earning investments	727,056	274,980
Total cash and cash equivalents	1,113,935	728,412
Equity securities, at fair value	72,158	52,507
Investment securities - available-for-sale, at fair value (amortized cost $7,592,765 and $7,772,603, respectively)	6,687,066	6,773,712
Investment securities - held-to-maturity, at amortized cost (fair value $2,663,374 and $2,643,682, respectively)	3,071,190	3,089,147
Federal Home Loan Bank/Federal Reserve Bank stock, at cost	413,326	314,168
Loans held for sale, at fair value	10,584	11,926
Loans:
Total loans	31,822,374	31,123,641
Allowance for credit losses on loans	(298,711)	(303,671)
Net loans	31,523,663	30,819,970
Premises and equipment, net	566,758	557,307
Operating lease right-of-use assets	183,687	189,714
Accrued interest receivable	188,988	190,521
Goodwill	1,998,716	1,998,716
Other intangible assets	120,219	126,405
Company-owned life insurance	770,471	768,552
Other assets	1,121,883	1,142,315
Total assets	47,842,644	46,763,372
Deposits:
Noninterest-bearing demand	10,995,083	11,930,798
Interest-bearing:
Checking and NOW	7,903,520	8,340,955
Savings	6,030,255	6,326,158
Money market	5,867,239	5,389,139
Time deposits	4,121,695	3,013,780
Total deposits	34,917,792	35,000,830
Federal funds purchased and interbank borrowings	618,955	581,489
Securities sold under agreements to repurchase	393,018	432,804
Federal Home Loan Bank advances	4,981,612	3,829,018
Other borrowings	746,869	743,003
Operating lease liabilities	205,249	211,964
Accrued expenses and other liabilities	701,723	835,669
Total liabilities	42,565,218	41,634,777
Shareholders' Equity
Preferred stock, 2,000 shares authorized, 231 shares issued and outstanding	230,500	230,500
Common stock, no par value, $1.00 per share stated value, 600,000 shares authorized,    291,922 and 292,903 shares issued and outstanding, respectively	291,922	292,903
Capital surplus	4,144,730	4,174,265
Retained earnings	1,318,632	1,217,349
Accumulated other comprehensive income (loss), net of tax	(708,358)	(786,422)
Total shareholders' equity	5,277,426	5,128,595
Total liabilities and shareholders' equity	$ 47,842,644	$ 46,763,372
Preferred stock, shares outstanding (in shares)	231	231
Preferred stock, shares issued (in shares)	231	231
Commercial
Loans:
Total loans	$ 9,751,875	$ 9,508,904
Allowance for credit losses on loans	(125,768)	(120,612)
Commercial real estate
Loans:
Total loans	12,908,380	12,457,070
Allowance for credit losses on loans	(135,348)	(138,244)
Residential real estate
Loans:
Total loans	6,568,666	6,460,441
Allowance for credit losses on loans	(20,207)	(21,916)
Consumer credit, net of unearned income
Loans:
Total loans	$ 2,593,453	$ 2,697,226