Loans and Leases - Troubled Debt Restructurings (Detail) - Lease Financing, net $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($) Contract	Dec. 31, 2017 USD ($) Contract
Financing Receivable, Modifications [Line Items]
Loans or leases modified in trouble debt restructuring \| Contract	52	74
Troubled debt restructurings, recorded investment	$ 30.8	$ 24.5
Troubled debt restructurings, unpaid principal balance	$ 34.2	$ 26.5
Commercial
Financing Receivable, Modifications [Line Items]
Loans or leases modified in trouble debt restructuring \| Contract	3	5
Troubled debt restructurings, recorded investment	$ 3.1	$ 2.2
Troubled debt restructurings, unpaid principal balance	$ 3.3	$ 3.2
Commercial \| Commercial and Institutional
Financing Receivable, Modifications [Line Items]
Loans or leases modified in trouble debt restructuring \| Contract	1	3
Troubled debt restructurings, recorded investment	$ 0.3	$ 0.4
Troubled debt restructurings, unpaid principal balance	$ 0.5	$ 1.4
Commercial \| Real Estate
Financing Receivable, Modifications [Line Items]
Loans or leases modified in trouble debt restructuring \| Contract	2	2
Troubled debt restructurings, recorded investment	$ 2.8	$ 1.8
Troubled debt restructurings, unpaid principal balance	$ 2.8	$ 1.8
Personal
Financing Receivable, Modifications [Line Items]
Loans or leases modified in trouble debt restructuring \| Contract	49	69
Troubled debt restructurings, recorded investment	$ 27.7	$ 22.3
Troubled debt restructurings, unpaid principal balance	$ 30.9	$ 23.3
Personal \| Real Estate
Financing Receivable, Modifications [Line Items]
Loans or leases modified in trouble debt restructuring \| Contract	48	66
Troubled debt restructurings, recorded investment	$ 27.7	$ 22.1
Troubled debt restructurings, unpaid principal balance	$ 30.8	$ 22.8
Personal \| Private Client
Financing Receivable, Modifications [Line Items]
Loans or leases modified in trouble debt restructuring \| Contract	1	3
Troubled debt restructurings, recorded investment	$ 0.0	$ 0.2
Troubled debt restructurings, unpaid principal balance	$ 0.1	$ 0.5

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Financing Receivable, Modifications, Unpaid Principal Balance

+ References

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Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524

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