Derivative Financial Instruments (Changes In Fair Value Of Non-Hedge Accounting Derivatives) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Derivative [Line Items]
Fair value of non-hedge accounting derivatives, Interest Income	$ 403	$ 234	$ 1,080	$ 657
Fair value of non-hedge accounting derivatives, MTM (Loss) Gain	819	(104)	2,664	(792)
Fair value of non-hedge accounting derivatives, Net Impact	1,222	130	3,744	(135)
Visa Swap [Member]
Derivative [Line Items]
Fair value of non-hedge accounting derivatives, Interest Income
Fair value of non-hedge accounting derivatives, MTM (Loss) Gain	(60)	(17)	(532)	(134)
Fair value of non-hedge accounting derivatives, Net Impact	(60)	(17)	(532)	(134)
Commercial Loan Interest Rate Derivatives, Net [Member]
Derivative [Line Items]
Fair value of non-hedge accounting derivatives, Interest Income	403	234	1,080	657
Fair value of non-hedge accounting derivatives, MTM (Loss) Gain	1,108	889	3,208	1,155
Fair value of non-hedge accounting derivatives, Net Impact	1,511	1,123	4,288	1,812
Fed Funds Futures Contracts [Member]
Derivative [Line Items]
Fair value of non-hedge accounting derivatives, Interest Income
Fair value of non-hedge accounting derivatives, MTM (Loss) Gain	(229)	(976)	(12)	(1,813)
Fair value of non-hedge accounting derivatives, Net Impact	$ (229)	$ (976)	$ (12)	$ (1,813)