Allowance for Loan Losses - Troubled Debt Restructurings (Detail) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2018 USD ($) SecurityLoan	Dec. 31, 2017 USD ($) SecurityLoan
Financing Receivable, Modifications [Line Items]
Number \| SecurityLoan	3	26
Pre-mod outstanding principal balance	$ 638	$ 7,111
Post-mod outstanding principal balance	643	6,978
Financial impact due to TDR taken as additional provision	$ 11	$ 133
Number that defaulted during the period \| SecurityLoan	1	5
Recorded investment of TDRs that defaulted during the period	$ 169	$ 624
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions		$ (5)
Mortgage Loans on Real Estate [Member] \| Residential [Member]
Financing Receivable, Modifications [Line Items]
Number \| SecurityLoan		1
Pre-mod outstanding principal balance		$ 939
Post-mod outstanding principal balance		939
Financial impact due to TDR taken as additional provision		$ 169
Number that defaulted during the period \| SecurityLoan		2
Recorded investment of TDRs that defaulted during the period		$ 223
Mortgage Loans on Real Estate [Member] \| Commercial [Member]
Financing Receivable, Modifications [Line Items]
Number \| SecurityLoan	1	8
Pre-mod outstanding principal balance	$ 384	$ 3,721
Post-mod outstanding principal balance	384	3,695
Financial impact due to TDR taken as additional provision	$ 11	$ (111)
Number that defaulted during the period \| SecurityLoan	1	1
Recorded investment of TDRs that defaulted during the period	$ 169	$ 219
Consumer [Member] \| Home Equity Lines of Credit [Member]
Financing Receivable, Modifications [Line Items]
Number \| SecurityLoan	1	3
Pre-mod outstanding principal balance	$ 133	$ 187
Post-mod outstanding principal balance	$ 138	187
Financial impact due to TDR taken as additional provision		$ 27
Number that defaulted during the period \| SecurityLoan		1
Recorded investment of TDRs that defaulted during the period		$ 127
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions		$ (5)
Consumer [Member] \| Home Equity Loans [Member]
Financing Receivable, Modifications [Line Items]
Number \| SecurityLoan	1	1
Pre-mod outstanding principal balance	$ 121	$ 252
Post-mod outstanding principal balance	$ 121	$ 252
Number that defaulted during the period \| SecurityLoan		1
Recorded investment of TDRs that defaulted during the period		$ 55
Consumer [Member] \| Other Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number \| SecurityLoan		1
Pre-mod outstanding principal balance		$ 14
Post-mod outstanding principal balance		14
Financial impact due to TDR taken as additional provision		$ 11
Consumer and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Number \| SecurityLoan		11
Pre-mod outstanding principal balance		$ 1,854
Post-mod outstanding principal balance		1,747
Financial impact due to TDR taken as additional provision		$ 37
Construction [Member] \| Residential [Member]
Financing Receivable, Modifications [Line Items]
Number \| SecurityLoan		1
Pre-mod outstanding principal balance		$ 144
Post-mod outstanding principal balance		$ 144

Financial Impact due to troubled debt restructure additional provision.

No definition available.

Name:	tcbk_FinancialImpactDueToTroubledDebtRestructureAdditionalProvision
Namespace Prefix:	tcbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Financial Impact due to troubled debt restructure charge offs or additional provision.

+ References

No definition available.

+ Details

Name:	tcbk_FinancialImpactDueToTroubledDebtRestructureChargeOffsOrAdditionalProvision
Namespace Prefix:	tcbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FinancingReceivableModificationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953682-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=tcbk_RealEstateMortgagePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ResidentialMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CommercialLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_HomeEquityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=tcbk_OtherConsumerLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=tcbk_ConsumerAndIndustrialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=tcbk_ConstructionPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: