TriCo Bancshares Condensed Financial Statements (Parent Only) - Condensed Statements of Cash Flows (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities:
Net income	$ 12,533	$ 12,199	$ 9,405	$ 10,674	$ 11,422	$ 12,694	$ 11,366	$ 8,336	$ 44,811	$ 43,818	$ 26,108
Adjustments to reconcile net income to net cash provided by operating activities:
Equity compensation vesting expense									1,467	1,370	1,133
Net cash from operating activities									48,226	54,817	27,417
Financing activities:
Repurchase of common stock									(1,890)	(412)	(292)
Cash dividends paid - common									(13,695)	(11,849)	(7,807)
Net cash from financing activities									93,316	242,226	163,667
Net change in cash and cash equivalents									2,151	(307,267)	12,360
Cash and cash equivalents and beginning of year				303,461				610,728	303,461	610,728	598,368
Cash and cash equivalents at end of year	305,612				303,461				305,612	303,461	610,728
Parent [Member]
Operating activities:
Net income									44,811	43,818	26,108
Adjustments to reconcile net income to net cash provided by operating activities:
Undistributed equity in earnings of Tri Counties Bank									(29,764)	(32,131)	(20,720)
Equity compensation vesting expense									1,467	1,370	1,133
Equity compensation tax effect									(155)	68	(225)
Net change in other assets and liabilities									(1,210)	(1,120)	671
Net cash from operating activities									15,149	12,005	6,967
Financing activities:
Issuance of common stock through option exercise									518	660	616
Equity compensation tax effect									155	(68)	225
Repurchase of common stock									(1,890)	(412)	(292)
Cash dividends paid - common									(13,695)	(11,849)	(7,807)
Net cash from financing activities									(14,912)	(11,669)	(7,258)
Net change in cash and cash equivalents									237	336	(291)
Cash and cash equivalents and beginning of year				$ 2,565				$ 2,229	2,565	2,229	2,520
Cash and cash equivalents at end of year	$ 2,802				$ 2,565				$ 2,802	$ 2,565	$ 2,229