Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 24, 2020	Jun. 30, 2019
Document And Entity Information [Abstract]
Document Type	10-K
Document Period End Date	Dec. 31, 2019
Entity File Number	0-10661
Entity Registrant Name	TriCo Bancshares
Entity Incorporation, State or Country Code	CA
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
Title of 12(b) Security	Common Stock
Trading Symbol	TCBK
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 1,003,743,000
Entity Common Stock, Shares Outstanding		30,432,929
Document Annual Report	true
Document Transition Report	false
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Central Index Key	0000356171
Current Fiscal Year End Date	--12-31