TriCo Bancshares Condensed Financial Statements (Parent Only) - Condensed Statements of Income (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed Financial Statements, Captions [Line Items]
Net interest expense	$ (1,241)	$ (1,395)	$ (1,396)	$ (1,476)	$ (1,659)	$ (1,984)	$ (2,489)	$ (3,325)	$ (5,508)	$ (9,457)	$ (15,375)
Income before income taxes	38,626	38,956	39,129	46,992	32,407	24,228	8,522	22,193	163,703	87,350	126,822
Equity in net income of Tri Counties Bank:
Income tax benefit	(10,404)	(11,534)	(10,767)	(13,343)	(8,750)	(6,622)	(1,092)	(6,072)	(46,048)	(22,536)	(34,750)
Net income	$ 28,222	$ 27,422	$ 28,362	$ 33,649	$ 23,657	$ 17,606	$ 7,430	$ 16,121	117,655	64,814	92,072
Parent
Condensed Financial Statements, Captions [Line Items]
Net interest expense									(2,128)	(2,555)	(3,272)
Administration expense									(985)	(932)	(877)
Income before income taxes									(3,113)	(3,487)	(4,149)
Equity in net income of Tri Counties Bank:
Distributed									31,571	63,419	32,669
Undistributed									88,289	3,851	62,326
Income tax benefit									908	1,031	1,226
Net income									$ 117,655	$ 64,814	$ 92,072