Derivative Financial Instruments (Schedule of Amounts Related to Interest Rate Derivatives Designated as Hedges of Fair Value) (Detail) - Designated as Hedging Instrument [Member] - Commercial Loan/Lease Interest Rate Swaps [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest Income on Loans [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount included in income or expense	$ (111)	$ 86	$ 25
Other Non-Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount included in income or expense	$ 9	$ 0	$ (1)