Derivative Instruments (Schedule of Notional Amounts of Derivative Instruments) (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Interest Rate Swaps [Member]
Notional Amount of Derivatives	$ 500,548	$ 498,071
Interest Rate Caps [Member]
Notional Amount of Derivatives	30,236	31,736
Credit Risk Participation Agreements [Member]
Notional Amount of Derivatives	43,441	40,661
Foreign Exchange (Forward Contracts) [Member]
Notional Amount of Derivatives	70,149	25,867
Foreign Exchange (Option Contracts) [Member]
Notional Amount of Derivatives	3,224
Mortgage Loan Commitments [Member]
Notional Amount of Derivatives	18,096	12,125
Mortgage Loan Forward Sale Contracts [Member]
Notional Amount of Derivatives	21,918	24,112
Total Notional Amount [Member]
Notional Amount of Derivatives	$ 687,612	$ 632,572