Allowance for Credit Losses on Loans - Additional Information (Detail) - Financial Asset Originated - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Loans and Leases Receivable Disclosure [Line Items]
Interest lost on nonaccrual loans	$ 303	$ 325	$ 1,162	$ 1,014
Interest income on nonaccrual loans	187	$ 151	$ 321	$ 297
Changes in California Unemployment and Gross Domestic Product
Loans and Leases Receivable Disclosure [Line Items]
Increase in allowance for credit loss	9,556
Reserve for concentration risk	(1,472)
Reserves on individually evaluated loans	$ (321)

Financing Receivable, Allowance For Credit Losses, Individually Evaluated For Impairment, Increase (Decrease)

No definition available.

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

- Definition

Financing Receivable, Allowance For Credit Losses, Reserve For Concentration Risk, Increase (Decrease)

+ References

No definition available.

+ Details

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

- Definition

Amount of increase (decrease) in allowance for credit loss on financing receivable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of interest income on financing receivable on nonaccrual status.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919258-210447

+ Details

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

- Definition

Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118939409&loc=d3e18794-111554

+ Details

Name:	us-gaap_LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_CreditLossStatusAxis=us-gaap_FinancialAssetOriginatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_UnusualOrInfrequentItemAxis=tcbk_ChangesInCaliforniaUnemploymentAndGrossDomesticProductMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: