Investment Securities - Securities Sold, Pledged as Collateral and Transfers (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Available-for-sale:
Sales proceeds	$ 66,081,000	$ 16,972,000
Gross realized gains	214,000	27,000
Gross realized losses	159,000	106,000
Securities transferred from available-for-sale to held-to-maturity	0	27,422,000
Unrealized pre-tax loss from transfer of available-for-sale securities to held-to-maturity		278,000
Amortization of net unrealized losses on securities transferred from available-for-sale to held-to-maturity	445,000	516,000
Public Deposits
Available-for-sale:
Available-for-sale securities pledged as collateral	126,598,000	125,696,000
Trust Deposits
Available-for-sale:
Available-for-sale securities pledged as collateral	742,000	734,000
State of California
Available-for-sale:
Available-for-sale securities pledged as collateral	127,340,000	126,430,000
Internal checking account
Available-for-sale:
Available-for-sale securities pledged as collateral	$ 622,000	$ 2,000,000

Amortization Of Net Unrealized Loss On Available-For-Sale Securities Transferred To Held-To-Maturity

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- Definition

Available-for-sale Securities, Transferred to Held-to-maturity Securities

+ References

No definition available.

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Available-for-sale Securities, Transferred to Held-to-maturity Securities, Unrealized Gain (Loss)

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- Definition

Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27357-111563

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Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Sum of the carrying amounts as of the date of the latest financial statement presented of securities which are owned but transferred to another party to serve as collateral to partially or fully secure a debt obligation, repurchase agreement or other current or potential obligation, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)(i)
-URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729

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- Definition

Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118954083&loc=d3e26853-111562

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3151-108585

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-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585

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