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Income Taxes - Effective Income Tax Reconciliation (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Effective Income Tax Rate Reconciliation, Percent
Federal statutory income tax rate	21.00%	21.00%	21.00%
California franchise tax, net of federal tax benefit	8.10%	8.20%	8.00%
Tax exempt interest on municipal securities and loans	(2.40%)	(1.80%)	(2.40%)
Tax exempt earnings on bank owned life insurance	(0.50%)	(0.60%)	(0.40%)
Low income housing and qualified zone academy bond tax credits	(0.50%)	(0.40%)	(0.50%)
Stock-based compensation and excess tax benefits	(0.20%)	(0.10%)	(0.60%)
Other	0.00%	(0.90%)	(0.20%)
Effective Tax Rate	25.50%	25.40%	24.90%

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- Definition

Effective Income Tax Rate Reconciliation, Deduction, Share-Based Compensation And Excess Tax Benefits

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Effective Income Tax Rate Reconciliation, Tax Credit, Affordable Housing

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Effective Income Tax Rate Reconciliation, Tax Exempt Income, Earnings on Bank Owned Life Insurance

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Effective Income Tax Rate Reconciliation, Tax Exempt Income, Interest on Municipal Securities and Loans

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 6.I.Fact.4)
-URI http://asc.fasb.org/extlink&oid=116825942&loc=d3e330036-122817

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 6.I.Fact.4)
-URI http://asc.fasb.org/extlink&oid=116825942&loc=d3e330036-122817

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