Derivative Financial Instruments (Schedule of the changes in the fair value of non-hedge accounting derivatives) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivative [Line Items]
Total impact on non-interest income	$ 4,265	$ 4,280	$ 3,124
Operating Expense [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Total impact on non-interest income	4,361	4,482	3,244
Operating Expense [Member] | Not Designated as Hedging Instrument [Member] | Credit Risk Contract [Member]
Derivative [Line Items]
Total impact on non-interest income	(33)	51	0
Operating Expense [Member] | Not Designated as Hedging Instrument [Member] | Other Contract [Member]
Derivative [Line Items]
Total impact on non-interest income	$ (63)	$ (253)	$ (120)