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, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Interest Income on Loans [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) included in income	$ (493)	$ (609)	$ (1,548)	$ (1,841)
Other Non-Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) included in income	$ 12	$ 11	$ 12	$ 17