Real Estate Owned (REO) - Additional Information (Details)	12 Months Ended
Dec. 31, 2017 USD ($) a Property	Dec. 31, 2016 USD ($) Property
Real Estate Owned REO Details [Line Items]
Property purchased at estimated net realizable value \| $		$ 2,265,000
Mortgages payable \| $	$ 0	$ 0
Non Rental Held For Sale [Member] \| Residential Single Family [Member]
Real Estate Owned REO Details [Line Items]
Number of Real Estate Properties	3
Los Angeles [Member] \| Condominium Complex [Member]
Real Estate Owned REO Details [Line Items]
Number of Units in Real Estate Property	42	70
Gains (Losses) on Sales of Other Real Estate (in Dollars) \| $	$ 595,000	$ 206,000
Los Angeles [Member] \| Condominium Complex [Member] \| Property 2 [Member]
Real Estate Owned REO Details [Line Items]
Number of Units in Real Estate Property		126
Gains (Losses) on Sales of Other Real Estate (in Dollars) \| $		$ 862,000
Los Angeles [Member] \| Sold [Member] \| Condominium Complex [Member]
Real Estate Owned REO Details [Line Items]
Number of Units in Real Estate Property	36	28
Los Angeles [Member] \| Sold [Member] \| Condominium Complex [Member] \| Property 2 [Member]
Real Estate Owned REO Details [Line Items]
Number of Units in Real Estate Property		126
Los Angeles [Member] \| Rental Property Held For Sale [Member] \| Condominium Complex [Member]
Real Estate Owned REO Details [Line Items]
Number of Units in Real Estate Property	6
San Francisco County [Member] \| Condominium Complex [Member]
Real Estate Owned REO Details [Line Items]
Number of Units in Real Estate Property	8	13
Gains (Losses) on Sales of Other Real Estate (in Dollars) \| $	$ 643,000	$ 704,000
San Francisco County [Member] \| Sold [Member] \| Condominium Complex [Member]
Real Estate Owned REO Details [Line Items]
Number of Units in Real Estate Property	5	5
San Francisco County [Member] \| Rental Property Held For Sale [Member] \| Condominium Complex [Member]
Real Estate Owned REO Details [Line Items]
Number of Units in Real Estate Property	3
Ventura [Member] \| Parking Lot [Member]
Real Estate Owned REO Details [Line Items]
Gains (Losses) on Sales of Other Real Estate (in Dollars) \| $	$ 71,000
Ventura [Member] \| Sold [Member] \| Parking Lot [Member]
Real Estate Owned REO Details [Line Items]
Number of Units in Real Estate Property	3
Ventura [Member] \| Acquired [Member] \| Parking Lot [Member]
Real Estate Owned REO Details [Line Items]
Number of Real Estate Properties		1
Ventura [Member] \| Acquired [Member] \| Commercial/Retail Property [Member]
Real Estate Owned REO Details [Line Items]
Number of Real Estate Properties		1
Alameda County [Member] \| Condominium Complex [Member]
Real Estate Owned REO Details [Line Items]
Number of Units in Real Estate Property		4
Gains (Losses) on Sales of Other Real Estate (in Dollars) \| $		$ 857,000
Alameda County [Member] \| Sold [Member] \| Condominium Complex [Member]
Real Estate Owned REO Details [Line Items]
Number of Units in Real Estate Property		4
Contra Costa [Member] \| Condominium Complex [Member]
Real Estate Owned REO Details [Line Items]
Number of Units in Real Estate Property		29
Gains (Losses) on Sales of Other Real Estate (in Dollars) \| $		$ 36,000
Contra Costa [Member] \| Condominium Complex [Member] \| First Deed of Trust [Member]
Real Estate Owned REO Details [Line Items]
Interest rate percentage on note		5.00%
Note, frequency of periodic payment		monthly
Note, maturity term		18 months
Note, maturity date		Mar. 01, 2018
Contra Costa [Member] \| Sold [Member] \| Condominium Complex [Member]
Real Estate Owned REO Details [Line Items]
Number of Units in Real Estate Property		29
Percentage of Real Estate Sale Price Based On Market Rates		77.00%
Contra Costa [Member] \| Rental Property Held For Sale [Member] \| Commercial Property [Member]
Real Estate Owned REO Details [Line Items]
Number of Real Estate Properties	1
Amador [Member] \| Commercial Property [Member] \| First Deed of Trust [Member]
Real Estate Owned REO Details [Line Items]
Interest rate percentage on note		5.00%
Note, frequency of periodic payment		monthly
Note, maturity term		5 years
Note, maturity date		Dec. 01, 2021
Amador [Member] \| Sold [Member] \| Commercial Property [Member]
Real Estate Owned REO Details [Line Items]
Gains (Losses) on Sales of Other Real Estate (in Dollars) \| $		$ 0
Percentage of Real Estate Sale Price Based On Market Rates		70.00%
Number of Real Estate Properties		1
Stanislaus County [Member] \| Affiliated Funds [Member]
Real Estate Owned REO Details [Line Items]
Acquired remaining percentage of interest in commercial land		36.00%
Property purchased at estimated net realizable value \| $		$ 878,000
Stanislaus County [Member] \| Non Rental Held For Sale [Member] \| Residential Single Family [Member]
Real Estate Owned REO Details [Line Items]
Area of Real Estate Property (in Acres) \| a	14
Fresno County California [Member] \| Non Rental Held For Sale [Member] \| Residential Single Family [Member]
Real Estate Owned REO Details [Line Items]
Number of Units in Real Estate Property	1
Marin County [Member] \| Non Rental Held For Sale [Member] \| Residential Single Family [Member]
Real Estate Owned REO Details [Line Items]
Area of Real Estate Property (in Acres) \| a	13

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Area of a real estate property.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Description of the frequency of periodic payments (monthly, quarterly, annual).

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The net gain (loss) resulting from sales and other disposals of other real estate owned, increases (decreases) in the valuation allowance for foreclosed real estate, and write-downs of other real estate owned after acquisition or physical possession.

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The number of real estate properties owned as of the balance sheet date.

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