| Cover | Jul. 27, 2021 | Apr. 28, 2021 | Jun. 30, 2021 |
| Cover [Abstract] | |||
| Document Type | 8-K | ||
| Document Period End Date | Jul. 27, 2021 | ||
| Entity Registrant Name | TriCo Bancshares | ||
| Entity Incorporation, State or Country Code | CA | ||
| Entity File Number | 0-10661 | ||
| Entity Tax Identification Number | 94-2792841 | ||
| Entity Address, Address Line One | 63 Constitution Drive | ||
| Entity Address, City or Town | Chico, | ||
| Entity Address, State or Province | CA | ||
| Entity Address, Postal Zip Code | 95973 | ||
| City Area Code | 530 | ||
| Local Phone Number | 898-0300 | ||
| Written Communications | true | ||
| Soliciting Material | false | ||
| Pre-commencement Tender Offer | false | ||
| Pre-commencement Issuer Tender Offer | false | ||
| Title of 12(b) Security | Common Stock, no par value | ||
| Trading Symbol | TCBK | ||
| Security Exchange Name | NASDAQ | ||
| Entity Emerging Growth Company | false | ||
| Amendment Flag | false | ||
| Entity Central Index Key | 0000356171 |
