TriCo Bancshare Condensed Financial Statements (Parent Only) - Statements of Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended							9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2016	Sep. 30, 2015
Condensed Financial Statements, Captions [Line Items]
Net income	$ 12,199	$ 9,405	$ 10,674	$ 11,422	$ 12,694	$ 11,366	$ 8,336	$ 32,278	$ 32,396
Other comprehensive income (loss), net of tax:
Unrealized holding (losses) gains on available for sale securities arising during the period	(1,193)				2,316			6,514	(429)
Change in minimum pension liability	(74)				(112)			(222)	(334)
Change in joint beneficiary liability	(1)							(5)
Other comprehensive (loss) income	(1,120)				2,428			6,731	(95)
Comprehensive income	11,079				15,122			39,009	32,301
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	12,199				12,694			32,278	32,396
Other comprehensive income (loss), net of tax:
Unrealized holding (losses) gains on available for sale securities arising during the period	(1,193)				2,316			6,514	(429)
Change in minimum pension liability	74				112			222	334
Change in joint beneficiary liability	(1)							(5)
Other comprehensive (loss) income	(1,120)				2,428			6,731	(95)
Comprehensive income	$ 11,079				$ 15,122			$ 39,009	$ 32,301