Borrowings and Subordinated Debentures (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Debt Instruments Weighted Average Remaining Maturity Period	3 years 4 months 20 days
Unsecured Debt [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 80,000,000
Unused lines of Credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Amount Outstanding	0	$ 0
Federal Home Loan Bank of San Francisco [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Borrowing Capacity, Description	99,000,000
Line of Credit Facility, Amount Outstanding	0
Federal Reserve Bank Advances [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Borrowing Capacity, Description	2,100,000,000
Line of Credit Facility, Amount Outstanding	0	0
Loans Pledged as Collateral	2,900,000,000
Federal Home Loan Bank Advances [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Borrowing Capacity, Description	2,500,000,000
Line of Credit Facility, Amount Outstanding	$ 618,000,000	$ 380,000,000