XML 50 R38.htm IDEA: XBRL DOCUMENT
v3.21.1

Investment Securities - Additional Information (Detail) | 3 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2021 USD ($) investmentSecurity | Dec. 31, 2020 USD ($) | Mar. 31, 2020 USD ($)
Investment Securities [Line Items] |  |  |
Securities pledged as collateral | $ 417,528,000 | $ 429,049,000 |
Residential real estate mortgage-backed securities | $ 1,069,850,000,000 |  |
Life of mortgage-backed securities | 4 years 6 months 29 days |  |
Impairment losses recognized | $ 0 |  |
Allowance for Credit Losses | 0 | 0 | $ 0
Obligations of U.S. government agencies |  |  |
Investment Securities [Line Items] |  |  |
Allowance for Credit Losses | $ 0 | 0 |
Number of available for sale securities in unrealized loss position (in investment securities) | investmentSecurity | 29 |  |
Percentage of aggregate depreciation in unrealized losses | 1.15% |  |
Obligations of states and political subdivisions |  |  |
Investment Securities [Line Items] |  |  |
Allowance for Credit Losses | $ 0 | 0 |
Number of available for sale securities in unrealized loss position (in investment securities) | investmentSecurity | 13 |  |
Percentage of aggregate depreciation in unrealized losses | 3.92% |  |
Asset backed securities |  |  |
Investment Securities [Line Items] |  |  |
Allowance for Credit Losses | $ 0 | $ 0 |
Number of available for sale securities in unrealized loss position (in investment securities) | investmentSecurity | 27 |  |
Percentage of aggregate depreciation in unrealized losses | 0.93% |  |

X
- Definition Investment Securities [Line Items] + References No definition available. + Details
Name: | tcbk_InvestmentSecuritiesLineItems
Namespace Prefix: | tcbk_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Life of mortgage backed securities. + References No definition available. + Details
Name: | tcbk_LifeOfMortgageBackedSecurities
Namespace Prefix: | tcbk_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of aggregate depreciation in unrealized losses. + References No definition available. + Details
Name: | tcbk_PercentageOfAggregateDepreciationInUnrealizedLosses
Namespace Prefix: | tcbk_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Securities Pledged as Collateral + References No definition available. + Details
Name: | tcbk_SecuritiesPledgedAsCollateral
Namespace Prefix: | tcbk_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of allowance for credit loss 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 326 -SubTopic 30 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118955579&loc=SL82922900-210455 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 9 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=118955579&loc=SL82922900-210455 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aaa) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 4 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=118955579&loc=SL82922888-210455 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The cumulative amount of credit losses recognized in earnings related to debt securities held for which a portion of an other than temporary impairment (OTTI) was recognized in other comprehensive income (a component of shareholders' equity). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118939692&loc=SL6284393-111563 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=118939692&loc=SL6284393-111563 + Details
Name: | us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Debt securities issued by a United States government agency such as Government National Mortgage Association (Ginnie Mae), Federal Home Loan Mortgage Corporation (Freddie Mac), and Federal National Mortgage Association (Fannie Mae), which are short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months. + References No definition available. + Details
Name: | us-gaap_USGovernmentAgenciesSecuritiesAtCarryingValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |