Federally Assisted Acquisition of San Joaquin Bank (Details Textual) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	Oct. 31, 2009	Dec. 31, 2011 Commercial Loan [Member]	Dec. 31, 2011 Single Family Residential Loan [Member]
Servicing Assets at Fair Value [Line Items]
Loss sharing agreement term		5 years	10 years
Loss recovery provision term		8 years	10 years
Additional Summary of the covered loans acquired in the acquisition (Textual) [Abstract]
Agreed percentage of loss in Loss sharing agreement	80.00%
Loss recoveries on covered assets	$ 144.0
Loss amount with respect to covered assets	26.7
Agreed percentage of reimbursement in Loss reimburse agreement	95.00%
After tax gain included in earnings due to purchase method	$ 12.3