TriCo Bancshares Condensed Financial Statements (Parent Only) - Statements of Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended							9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2015	Sep. 30, 2014
Condensed Financial Statements, Captions [Line Items]
Net income	$ 12,694	$ 11,366	$ 8,336	$ 5,650	$ 8,234	$ 4,859	$ 7,365	$ 32,396	$ 20,458
Other comprehensive income (loss), net of tax:
Unrealized holding gains (losses) on available for sale securities arising during the period	2,316				(398)			(429)	(77)
Change in minimum pension liability	112				6			334	16
Other comprehensive income (loss)	2,428				(392)			(95)	(61)
Comprehensive income	15,122				7,842			32,301	20,397
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	12,694				8,234			32,396	20,458
Other comprehensive income (loss), net of tax:
Unrealized holding gains (losses) on available for sale securities arising during the period	2,316				(398)			(429)	(77)
Change in minimum pension liability	112				6			334	16
Other comprehensive income (loss)	2,428				(392)			(95)	(61)
Comprehensive income	$ 15,122				$ 7,842			$ 32,301	$ 20,397