Derivative Financial Instruments (Schedule Of Notional Amounts And Estimated Fair Values Of Interest Rate Derivative Contracts Outstanding) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Notional Amount [Member] | Interest Rate Derivatives Designated As Hedges Of Fair Value [Member]
Derivatives, Fair Value [Line Items]
Commercial loan/lease interest rate swaps	$ 90,284	$ 71,181
Notional Amount [Member] | Interest Rate Derivatives Designated As Hedges Of Cash Flows [Member]
Derivatives, Fair Value [Line Items]
Interest rate swap on junior subordinated deferrable interest debentures	120,000	120,000
Notional Amount [Member] | Non-Hedging Interest Rate Derivatives [Member]
Derivatives, Fair Value [Line Items]
Commercial loan/lease interest rate swaps	721,036	613,883
Commercial loan/lease interest rate swaps	721,036	613,883
Commercial loan/lease interest rate caps	22,500	20,000
Commercial loan/lease interest rate caps	22,500	20,000
Estimated Fair Value [Member] | Interest Rate Derivatives Designated As Hedges Of Fair Value [Member]
Derivatives, Fair Value [Line Items]
Commercial loan/lease interest rate swaps	(7,952)	(8,376)
Estimated Fair Value [Member] | Interest Rate Derivatives Designated As Hedges Of Cash Flows [Member]
Derivatives, Fair Value [Line Items]
Interest rate swap on junior subordinated deferrable interest debentures	(5,392)	(7,807)
Estimated Fair Value [Member] | Non-Hedging Interest Rate Derivatives [Member]
Derivatives, Fair Value [Line Items]
Commercial loan/lease interest rate swaps	64,571	61,137
Commercial loan/lease interest rate swaps	(64,775)	(61,393)
Commercial loan/lease interest rate caps	16	50
Commercial loan/lease interest rate caps	$ (16)	$ (50)