Federal Home Loan Bank and Federal Reserve Bank Borrowings (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
FHLB Fixed Rate Advances, Maturities Summary [Abstract]
FHLB Fixed Rate Advances, Weighted Average Interest Rate, Over 5 through 10 years	5.66%
FHLB Fixed Rate Advances, Over 5 through 10 years	$ 1,000
FHLB Fixed Rate Advances, Weighted Average Interest Rate, Due after 10 years	5.37%
FHLB Fixed Rate Advances, Due after 10 years	5,000
FHLB Fixed Rate Advances, Total Amount before valuation adjustment	6,000
Valuation adjustment from acquisition accounting	644
FHLB Fixed Rate Advances, Total Amount	6,644
Federal Home Loan Bank, Advances, Activity for Year [Abstract]
FHLB Advances	6,644	119,009	119,405
Average balance during the year	100,337	120,419	123,685
Maximum month-end balance during the year	118,967	127,426	154,916
Weighted average rate during the year	2.79%	2.76%	2.75%
Weighted average rate at December 31	5.42%	2.81%	2.81%
FHLB Advances, Collateral Pledged	443,419	539,454
FHLB Borrowing Capacity	435,189	419,115
Federal Reserve Bank, Advances, Collateral Pledged	59,456	404,444
Federal Reserve Bank borrowing capacity	59,456	404,444
Securities Investment [Member]
Federal Home Loan Bank, Advances, Activity for Year [Abstract]
FHLB Advances, Collateral Pledged	0	77,414
Federal Reserve Bank, Advances, Collateral Pledged	45,641	53,122
Loans Receivable [Member]
Federal Home Loan Bank, Advances, Activity for Year [Abstract]
FHLB Advances, Collateral Pledged	443,419	462,040
Commercial Loan [Member]
Federal Home Loan Bank, Advances, Activity for Year [Abstract]
Federal Reserve Bank, Advances, Collateral Pledged	$ 13,815	$ 351,322