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Reserve for Unfunded Commitments - Summary of Activity in Reserve for Unfunded Commitments (Detail) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]    
Balance at beginning of period $ 2,145tcbk_ReserveForUnfundedCommitments $ 2,415tcbk_ReserveForUnfundedCommitments
Provision for losses - Unfunded commitments (130)tcbk_ProvisionForLossesUnfundedCommitments (185)tcbk_ProvisionForLossesUnfundedCommitments
Balance at end of period $ 2,015tcbk_ReserveForUnfundedCommitments $ 2,230tcbk_ReserveForUnfundedCommitments