Borrowing Arrangements (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Borrowing Arrangements
Investments securing FHLB advances, amortized cost	$ 507,477,000
Federal Funds Purchased	0	$ 400,000
Federal Home Loan Bank Advances \| Securities Pledged as Collateral
Borrowing Arrangements
Investments securing FHLB advances, amortized cost	428,000	584,000
Estimated Fair Value	465,000	637,000
San Fransisco Branch
Borrowing Arrangements
Advances from FHLB	$ 0	$ 0

This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount of debt securities categorized neither as held-to-maturity nor trading.

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Amount of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

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Amount of advances from the Federal Home Loan Bank (FHLB).

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