Short-term Borrowings (Short-term Borrowings) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Short-term Debt [Line Items]
Short-term borrowings	$ 224,626	$ 270,081
Securities sold under agreements to repurchase
Short-term Debt [Line Items]
Short-term borrowings	203,355	253,496
Federal funds purchased
Short-term Debt [Line Items]
Short-term borrowings	5,525	10,800
FHLB advance
Short-term Debt [Line Items]
Short-term borrowings	10,000	0
Notes payable to unaffiliated bank
Short-term Debt [Line Items]
Short-term borrowings	$ 5,746	$ 5,785