TriCo Bancshares Condensed Financial Statements (Parent Only) - Condensed Statements of Income (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Condensed Financial Statements, Captions [Line Items]
Net interest expense	$ (4,089)	$ (2,260)	$ (1,909)	$ (1,271)	$ (1,241)	$ (1,395)	$ (1,396)	$ (1,476)	$ (9,529)	$ (5,508)	$ (9,457)
Income before income taxes	51,066	51,486	43,112	28,243	38,626	38,956	39,129	46,992	173,907	163,703	87,350
Equity in net income of Tri Counties Bank:
Income tax benefit	(14,723)	(14,148)	(11,748)	(7,869)	(10,404)	(11,534)	(10,767)	(13,343)	(48,488)	(46,048)	(22,536)
Net income	$ 36,343	$ 37,338	$ 31,364	$ 20,374	$ 28,222	$ 27,422	$ 28,362	$ 33,649	125,419	117,655	64,814
Parent
Condensed Financial Statements, Captions [Line Items]
Net interest expense									(4,385)	(2,128)	(2,555)
Administration expense									(816)	(985)	(932)
Income before income taxes									(5,201)	(3,113)	(3,487)
Equity in net income of Tri Counties Bank:
Distributed									64,188	31,571	63,419
Undistributed									64,896	88,289	3,851
Income tax benefit									1,536	908	1,031
Net income									$ 125,419	$ 117,655	$ 64,814