Reserve for Unfunded Commitments - Summary of Activity in Reserve for Unfunded Commitments (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Balance at beginning of period	$ 3,164	$ 2,719
Change in reserve for unfunded commitments	700	15
Balance at end of period	$ 3,864	$ 2,734

Provision for reversal of losses unfunded commitments.

No definition available.

Name:	tcbk_ProvisionForReversalOfLossesUnfundedCommitments
Namespace Prefix:	tcbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration