TriCo Bancshares Condensed Financial Statements (Parent Only) - Condensed Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 768,421	$ 669,551
Other assets	109,025	84,172
Total assets	8,614,787	7,639,529
Liabilities and shareholders’ equity
Other liabilities	112,070	94,597
Junior subordinated debt	58,079	57,635
Total liabilities	7,614,603	6,714,415
Shareholders’ equity:
Preferred stock, value issued	0	0
Common stock, no par value: 50,000,000 shares authorized; issued and outstanding: 29,730,424 and 29,727,214 at December 31, 2021 and 2020, respectively	532,244	530,835
Retained earnings	466,959	381,999
Accumulated other comprehensive loss, net	981	12,280
Total shareholders’ equity	1,000,184	925,114	$ 906,570	$ 827,373
Total liabilities and shareholders’ equity	8,614,787	7,639,529
Parent
Assets
Cash and cash equivalents	4,950	13,297
Investment in Tri Counties Bank	1,047,577	967,949
Other assets	6,073	1,818
Total assets	1,058,600	983,064
Liabilities and shareholders’ equity
Other liabilities	337	315
Junior subordinated debt	58,079	57,635
Total liabilities	58,416	57,950
Shareholders’ equity:
Preferred stock, value issued	0	0
Common stock, no par value: 50,000,000 shares authorized; issued and outstanding: 29,730,424 and 29,727,214 at December 31, 2021 and 2020, respectively	532,244	530,835
Retained earnings	466,959	381,999
Accumulated other comprehensive loss, net	981	12,280
Total shareholders’ equity	1,000,184	925,114
Total liabilities and shareholders’ equity	$ 1,058,600	$ 983,064