Junior Subordinated Debt - Summary of Terms and Recorded Balance of Subordinated Debenture (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Subordinated Borrowing [Line Items]
Face Value	$ 62,889
Recorded Book Value	$ 57,232	$ 57,042
TriCo Cap Trust I
Subordinated Borrowing [Line Items]
Maturity Date	Oct. 07, 2033
Face Value	$ 20,619
Current Coupon Rate	5.04%
Recorded Book Value	$ 20,619	20,619
TriCo Cap Trust II
Subordinated Borrowing [Line Items]
Maturity Date	Jul. 23, 2034
Face Value	$ 20,619
Current Coupon Rate	4.48%
Recorded Book Value	$ 20,619	20,619
North Valley Trust II
Subordinated Borrowing [Line Items]
Maturity Date	Apr. 24, 2033
Face Value	$ 6,186
Current Coupon Rate	5.16%
Recorded Book Value	$ 5,215	5,174
North Valley Trust III
Subordinated Borrowing [Line Items]
Maturity Date	Apr. 24, 2034
Face Value	$ 5,155
Current Coupon Rate	4.73%
Recorded Book Value	$ 4,118	4,079
North Valley Trust IV
Subordinated Borrowing [Line Items]
Maturity Date	Mar. 15, 2036
Face Value	$ 10,310
Current Coupon Rate	3.22%
Recorded Book Value	$ 6,661	$ 6,551
LIBOR PLUS | TriCo Cap Trust I
Subordinated Borrowing [Line Items]
Coupon Rate (Variable) 3 mo. LIBOR +	3.05%
LIBOR PLUS | TriCo Cap Trust II
Subordinated Borrowing [Line Items]
Coupon Rate (Variable) 3 mo. LIBOR +	2.55%
LIBOR PLUS | North Valley Trust II
Subordinated Borrowing [Line Items]
Coupon Rate (Variable) 3 mo. LIBOR +	3.25%
LIBOR PLUS | North Valley Trust III
Subordinated Borrowing [Line Items]
Coupon Rate (Variable) 3 mo. LIBOR +	2.80%
LIBOR PLUS | North Valley Trust IV
Subordinated Borrowing [Line Items]
Coupon Rate (Variable) 3 mo. LIBOR +	1.33%