TriCo Bancshares Parent Only Financial Statements (Unaudited) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended						6 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Jun. 30, 2012	Jun. 30, 2011
Condensed Financial Statements, Captions [Line Items]
Net income	$ 5,321	$ 3,931	$ 6,549	$ 6,470	$ 2,771	$ 2,800	$ 9,252	$ 5,571
Other comprehensive income, net of tax:
Unrealized holding gains (losses) on available-for-sale securities, net of tax	(121)				1,558		(274)	1,334
Other comprehensive income	(121)				1,558		(274)	1,334
Comprehensive income	5,200				4,329		8,978	6,905
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	5,321				2,771		9,252	5,571
Other comprehensive income, net of tax:
Unrealized holding gains (losses) on available-for-sale securities, net of tax	(121)				1,558		(274)	1,334
Other comprehensive income	(121)				1,558		(274)	1,334
Comprehensive income	$ 5,200				$ 4,329		$ 8,978	$ 6,905