Derivative Financial Instruments (Schedule of Notional Amounts and Estimated Fair Values of Interest Rate Derivative Contracts) (Details) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Notional Amount [Member] | Interest Rate Derivatives Designated As Hedges of Fair Value [Member]
Commercial loan/lease interest rate swaps	$ 90,626	$ 104,088
Notional Amount [Member] | Interest Rate Derivatives Designated As Hedges of Cash Flows [Member]
Interest rate swaps on junior subordinated deferrable interest debentures	120,000	120,000
Notional Amount [Member] | Non-Hedging Interest Rate Derivatives [Member]
Commercial loan/lease interest rate swaps	582,074	593,792
Commercial loan/lease interest rate swaps (2)	582,074	593,792
Commercial loan/lease interest rate caps	20,000	20,000
Commercial loan/lease interest rate caps (2)	20,000	20,000
Estimated Fair Value [Member] | Interest Rate Derivatives Designated As Hedges of Fair Value [Member]
Commercial loan/lease interest rate swaps	(7,496)	(8,350)
Estimated Fair Value [Member] | Interest Rate Derivatives Designated As Hedges of Cash Flows [Member]
Interest rate swaps on junior subordinated deferrable interest debentures	(9,353)	(9,895)
Estimated Fair Value [Member] | Non-Hedging Interest Rate Derivatives [Member]
Commercial loan/lease interest rate swaps	44,270	44,335
Commercial loan/lease interest rate swaps (2)	(44,474)	(44,666)
Commercial loan/lease interest rate caps	226	388
Commercial loan/lease interest rate caps (2)	$ (226)	$ (388)