Allowance for Loan Losses - Additional Information (Detail) - USD ($)	3 Months Ended	6 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Originated [Member]
Loans and Leases Receivable Disclosure [Line Items]
Interest income on non accrual loans	$ 289,000	$ 341,000	$ 568,000	$ 626,000
Interest income on non accrual loans ,recognized	53,000	53,000	86,000	75,000
Impaired TDR Loans			10,998,000	9,450,000	$ 10,253,000
Obligations to lend additional funds on TDR			0	0	0
PNCI [Member]
Loans and Leases Receivable Disclosure [Line Items]
Interest income on non accrual loans	160,000	26,000	281,000	54,000
Interest income on non accrual loans ,recognized	$ 111,000	$ 12,000	171,000	11,000
Impaired TDR Loans			811,000	1,459,000	615,000
Obligations to lend additional funds on TDR			$ 0	$ 0	$ 0

Interest income recognized on nonaccrual loans.

No definition available.

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

- Definition

Obligation related to troubled debt restructuring.

+ References

No definition available.

+ Details

Name:	tcbk_ObligationRelatedToTroubledDebtRestructuring
Namespace Prefix:	tcbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of financing receivable modified as troubled debt restructuring.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=118939409&loc=d3e18845-111554

+ Details

Name:	us-gaap_FinancingReceivableModificationsRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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_CreditLossStatusAxis=tcbk_PurchaseNotCreditImpairedLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: