Loans (Narrative) (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Loans [Line Items]
Loans, net of unearned income	$ 35,280,547	$ 34,789,104	$ 33,171,233
Net deferred loan fees and costs and fair value accounting adjustments	59,300	50,800	(32,200)
Net deferred loan fees and costs and fair value accounting adjustments, paid by SBA under PPP	6,300
Commercial
Loans [Line Items]
Loans, net of unearned income	11,583,963	11,904,068	12,708,207
Commercial \| Commercial PPP loans
Loans [Line Items]
Loans, net of unearned income	253,964	558,283	3,292,982
Premium finance receivables
Loans [Line Items]
Unearned income portion of premium finance receivables	$ 140,300	$ 135,500	$ 114,400

Amount of fee received for commitment to originate or purchase financing receivable where likelihood of commitment being exercised is remote. Excludes financing receivable covered under loss sharing agreement.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 45
-Paragraph 2
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Amount excluding accrued interest, before allowance for credit loss, of financing receivable.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 5
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-Publisher FASB
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-Section 50
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Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

+ References

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-Publisher FASB
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Loans [Line Items]

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Unamortized Loan Commitment And Origination Fees And Unamortized Discounts Or Premiums, Paid By Small Business Administration Under Paycheck Protection Program

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