Other Borrowings (Details Textual) (USD $)	6 Months Ended		6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 Matured January 25, 2012, effective rate 0.24% [Member]	Jun. 30, 2012 Matured April 6, 2012, effective rate 0.26% [Member]	Jun. 30, 2012 Matured April 25, 2012, effective rate 0.26% [Member]	Jun. 30, 2012 Matures July 25, 2012, effective rate 0.34% [Member]	Jun. 30, 2012 Other collateralized borrowings, fixed rate, as of June 30, 2012 of 0.05% payable on July 2, 2012 [Member]	Jun. 30, 2012 Citizens [Member]	Sep. 23, 2011 Citizens [Member]
Other Borrowings (Textual) [Abstract]
Borrowings with principal balances assumed under Citizens acquisition								$ 3,000,000	$ 22,000,000
Borrowings with fair values assumed under Citizens acquisition								22,000,000	22,028,000
FHLB fixed rate borrowings effective rate	4.72%		0.24%	0.26%	0.26%	0.34%	0.05%
FHLB fixed rate borrowings maturity date	Aug. 30, 2012		Jan. 25, 2012	Apr. 06, 2012	Apr. 25, 2012	Jul. 25, 2012	Jul. 30, 2012
Other Borrowings (Additional Textual) [Abstract]
Repurchase investment securities sold and pledged as collateral under securities repurchase agreement	55,576,000
Average balance of repurchase agreements	50,000,000
Average rate of repurchase agreement	4.72%
Other collateralized borrowings	7,831,000	8,527,000
Repurchase investment securities sold and pledged as collateral under securities repurchase agreement	15,916,000
FHLB Collateral line of credit, maximum borrowings capacity	495,862,000
FHLB collateral line of credit, outstanding balance	3,000,000
FHLB collateral line of credit, remaining borrowing capacity	492,862,000
Loans designated as potential collateral under collateralized line of credit with FHLB	1,006,002,000
Collateralized line of credit with Federal Reserve Bank, maximum borrowings capacity	72,965,000
Collateralized line of credit with Federal Reserve Bank, outstanding balance	0
Collateralized line of credit with Federal Reserve Bank, remaining borrowing capacity	72,965,000
Investment securities designated as potential collateral under collateral line of credit with FRB	182,000
Loans designated as potential collateral under collateral line of credit with FRB	91,224,000
Unused correspondent banking lines of credit from commercial banks for federal funds	$ 5,000,000