Derivative Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Fair value of derivative financial instruments
Total Asset Derivative	$ 3,785	$ 2,849
Total Liability Derivative	8,343	7,101
Derivatives designated as hedging instruments [Member]
Fair value of derivative financial instruments
Total Asset Derivative	2,523	2,187
Total Liability Derivative	8,343	7,101
Derivatives designated as hedging instruments [Member] | Interest Rate Contracts One [Member] | Loans [Member]
Fair value of derivative financial instruments
Total Asset Derivative	443	754
Derivatives designated as hedging instruments [Member] | Interest Rate Contracts One [Member] | Other Liabilities [Member]
Fair value of derivative financial instruments
Total Liability Derivative	2,523	2,187
Derivatives designated as hedging instruments [Member] | Interest Rate Contracts Two [Member] | Other Assets [Member]
Fair value of derivative financial instruments
Total Asset Derivative	2,080	1,433
Derivatives designated as hedging instruments [Member] | Interest Rate Contracts Two [Member] | Other Liabilities [Member]
Fair value of derivative financial instruments
Total Liability Derivative	5,820	4,914
Derivatives not designated as hedging instruments [Member]
Fair value of derivative financial instruments
Total Asset Derivative	1,262	662
Total Liability Derivative
Derivatives not designated as hedging instruments [Member] | Mortgage loan contracts [Member] | Other Assets [Member]
Fair value of derivative financial instruments
Total Asset Derivative	1,262	662
Derivatives not designated as hedging instruments [Member] | Mortgage loan contracts [Member] | Other Liabilities [Member]
Fair value of derivative financial instruments
Total Liability Derivative