Loans and Leases (Investments in TDRs, Segregated by Risk Rating Exposure) (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total recorded investment of TDRs	$ 243,067	$ 230,414
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total recorded investment of TDRs	105,567	87,739
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (1) - (6) Pass [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total recorded investment of TDRs	19,295	13,165
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (7) Special Mention [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total recorded investment of TDRs	72	84
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (8) Substandard [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total recorded investment of TDRs	79,482	67,880
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (9) Doubtful [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total recorded investment of TDRs	$ 6,718	$ 6,610