Investment Securities (Details Textual) (USD $)	3 Months Ended		9 Months Ended				1 Months Ended
	Sep. 30, 2012 Security	Sep. 30, 2011	Sep. 30, 2012 Security	Sep. 30, 2011	May 31, 2012	Dec. 31, 2011 Security	Jun. 30, 2012 External Credit Rating, Moody's [Member] Corporate_Bond
Financing Receivable, Recorded Investment [Line Items]
Number of corporate bonds downgraded by Moody's							5
Investment Securities (Textual) [Abstract]
Number of available for sale investment securities in the less than twelve month category	3		3			10
Number of available for sale investment securities in the twelve month or more category	10		10			6
Reclassification of held-to-maturity investment portfolio to available for sale					$ 269,000,000
Increased total shareholders' equity by reclassification			5,500,000
Interest only strip security						2,894,000
Pledged investment securities	105,400,000		105,400,000			311,400,000
Proceeds from sale of available-for-sale investment securities	0	112,757,000	306,610,000	112,757,000
Net gains	0	1,413,000	9,006,000	1,413,000
Available-for-sale securities maturity period			2 years
Aggregate amortized cost of private - label securities	659,000		659,000			765,000
Aggregate fair value of private - label securities	$ 636,000		$ 636,000			$ 662,000