Loans and Leases (Information on How Loans and Leases were Modified as a TDR) (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) loan	Mar. 31, 2019 USD ($) loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans and Leases | loan	37	43
Post-Modification Recorded Investment | $	$ 30,239	$ 26,942
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Extended Maturity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans and Leases | loan	2	2
Post-Modification Recorded Investment | $	$ 104	$ 124
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Maturity/Rate Combined [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans and Leases | loan	5	1
Post-Modification Recorded Investment | $	$ 274	$ 25
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Other [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans and Leases | loan	10	15
Post-Modification Recorded Investment | $	$ 27,137	$ 22,027
Commercial Portfolio Segment [Member] | Commercial Real Estate | Extended Maturity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans and Leases | loan	0	0
Post-Modification Recorded Investment | $	$ 0	$ 0
Commercial Portfolio Segment [Member] | Commercial Real Estate | Maturity/Rate Combined [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans and Leases | loan	1	0
Post-Modification Recorded Investment | $	$ 278	$ 0
Commercial Portfolio Segment [Member] | Commercial Real Estate | Other [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans and Leases | loan	0	2
Post-Modification Recorded Investment | $	$ 0	$ 2,636
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Extended Maturity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans and Leases | loan	1	1
Post-Modification Recorded Investment | $	$ 264	$ 519
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Maturity/Rate Combined [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans and Leases | loan	3	5
Post-Modification Recorded Investment | $	$ 443	$ 451
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Other [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans and Leases | loan	3	2
Post-Modification Recorded Investment | $	$ 613	$ 261
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Extended Maturity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans and Leases | loan	0	2
Post-Modification Recorded Investment | $	$ 0	$ 145
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Maturity/Rate Combined [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans and Leases | loan	1	0
Post-Modification Recorded Investment | $	$ 13	$ 0
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Other [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans and Leases | loan	11	13
Post-Modification Recorded Investment | $	$ 1,113	$ 754