Junior Subordinated Debt - Additional Information (Detail) - USD ($)		9 Months Ended
	Oct. 03, 2014	Sep. 30, 2015	Dec. 31, 2014	Jun. 22, 2004	Jul. 31, 2003
Class of Stock [Line Items]
Common stock shares issued		22,764,295	22,714,964
Subordinated debenture, Face Value		$ 62,889,000
Subordinated debenture, recorded fair value		$ 56,420,000	$ 56,272,000
North Valley Bancorp [Member]
Class of Stock [Line Items]
Acquisition, completion date		Oct. 03, 2014
TriCo Capital Trust I [Member]
Class of Stock [Line Items]
Common stock shares issued					619
Common stock par value					$ 1,000
Issuance of common stock, aggregate value					$ 619,000
Issued Junior Subordinated Debenture to the trust					$ 20,619,000
Offering of cumulative trust preferred securities					20,000
Cumulative trust preferred securities for cash in an aggregate amount					$ 20,000,000
Redeem the trust preferred securities		Oct. 07, 2033
LIBOR Rate, Description		Three-month LIBOR plus 3.05%
Preferred securities redeemable interest rate		3.05%
Company paid underwriting fees, per trust preferred security		$ 7.50
Company paid underwriting fees aggregate		$ 150,000
Net proceeds were used to finance the opening of new branches, services and technology		19,850,000
Subordinated debenture, Face Value		20,619,000
Subordinated debenture, recorded fair value		$ 20,619,000
TriCo Capital Trust II [Member]
Class of Stock [Line Items]
Common stock shares issued				619
Common stock par value				$ 1,000
Issuance of common stock, aggregate value				$ 619,000
Issued Junior Subordinated Debenture to the trust				$ 20,619,000
Offering of cumulative trust preferred securities				20,000
Cumulative trust preferred securities for cash in an aggregate amount				$ 20,000,000
Redeem the trust preferred securities		Jul. 23, 2034
LIBOR Rate, Description		Three-month LIBOR plus 2.55%
Preferred securities redeemable interest rate		2.55%
Company paid underwriting fees, per trust preferred security		$ 2.50
Company paid underwriting fees aggregate		$ 50,000
Net proceeds were used to finance the opening of new branches, services and technology		19,950,000
Subordinated debenture, Face Value		20,619,000
Subordinated debenture, recorded fair value		20,619,000
North Valley Trust II [Member]
Class of Stock [Line Items]
Subordinated debenture, Face Value	$ 6,186,000	6,186,000
Acquisition of common stock interests	186,000
Subordinated debenture, recorded fair value	5,006,000	5,045,000
North Valley Trust III [Member]
Class of Stock [Line Items]
Subordinated debenture, Face Value	5,155,000	5,155,000
Acquisition of common stock interests	155,000
Subordinated debenture, recorded fair value	3,918,000	3,956,000
North Valley Trust IV [Member]
Class of Stock [Line Items]
Subordinated debenture, Face Value	10,310,000	10,310,000
Acquisition of common stock interests	310,000
Subordinated debenture, recorded fair value	$ 6,063,000	$ 6,181,000