TriCo Bancshares Condensed Financial Statements (Parent Only) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012
Condensed Statements of Comprehensive Income
Net income	$ 8,477	$ 4,722	$ 5,020	$ 5,321	$ 3,931
Other comprehensive loss, net of tax:
Decrease in unrealized gains on available-for-sale securities arising during the period	(621)				(153)
Other comprehensive loss	(621)				(153)
Comprehensive income	7,856				3,778
Parent [Member]
Condensed Statements of Comprehensive Income
Net income	8,477				3,931
Other comprehensive loss, net of tax:
Decrease in unrealized gains on available-for-sale securities arising during the period	(621)				(153)
Other comprehensive loss	(621)				(153)
Comprehensive income	$ 7,856				$ 3,778