Regulatory Capital - Summary of Company's and Bank's Actual Capital Amounts and Ratios (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Subtotal bank of commerce holdings [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Actual, Leverage capital (to average assets)Amount	$ 120,661	$ 125,935
Actual, Leverage capital (to average assets) Ratio	12.80%	13.13%
Capital Adequacy Purposes, leverage capital (to average assets) Amount	37,720	38,354
Capital Adequacy Purposes, leverage capital (to average assets) Ratio	4.00%	4.00%
Well Capitalized, leverage capital (to average assets) Amount
Well Capitalized, leverage capital (to average assets) Ratio
Actual, Tier1 capital (to risk-weighted assets) Amount	120,661	125,935
Actual, Tier1 capital (to risk-weighted assets) Ratio	15.94%	14.53%
Capital Adequacy Purpose, Tier1 capital (to risk-weighted assets) Amount	30,280	34,664
Capital Adequacy Purpose, Tier1 capital (to risk-weighted assets) Ratio	4.00%	4.00%
Well Capitalized, Tier1 capital (to risk-weighted assets) Amount
Well Capitalized, Tier1 capital (to risk-weighted assets) Ratio
Actual, Total capital (to risk-weighted assets) Amount	130,191	136,777
Actual, Total capital (to risk-weighted assets) Ratio	17.20%	15.78%
Capital Adequacy Purpose, Total capital (to risk-weighted assets) Amount	60,559	69,329
Capital Adequacy Purpose, Total capital (to risk-weighted assets) Ratio	8.00%	8.00%
Well Capitalized, Total capital (to risk-weighted assets) Ratio
Well Capitalized, Total capital (to risk-weighted assets) Amount
Commercial banking [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Actual, Leverage capital (to average assets)Amount	117,354	121,325
Actual, Leverage capital (to average assets) Ratio	12.49%	12.65%
Capital Adequacy Purposes, leverage capital (to average assets) Amount	37,595	38,354
Capital Adequacy Purposes, leverage capital (to average assets) Ratio	4.00%	4.00%
Well Capitalized, leverage capital (to average assets) Amount	46,994	47,943
Well Capitalized, leverage capital (to average assets) Ratio	5.00%	5.00%
Actual, Tier1 capital (to risk-weighted assets) Amount	117,354	121,325
Actual, Tier1 capital (to risk-weighted assets) Ratio	15.56%	14.06%
Capital Adequacy Purpose, Tier1 capital (to risk-weighted assets) Amount	30,173	34,518
Capital Adequacy Purpose, Tier1 capital (to risk-weighted assets) Ratio	4.00%	4.00%
Well Capitalized, Tier1 capital (to risk-weighted assets) Amount	45,260	51,777
Well Capitalized, Tier1 capital (to risk-weighted assets) Ratio	6.00%	6.00%
Actual, Total capital (to risk-weighted assets) Amount	126,850	132,122
Actual, Total capital (to risk-weighted assets) Ratio	16.82%	15.31%
Capital Adequacy Purpose, Total capital (to risk-weighted assets) Amount	60,347	69,036
Capital Adequacy Purpose, Total capital (to risk-weighted assets) Ratio	8.00%	8.00%
Well Capitalized, Total capital (to risk-weighted assets) Ratio	$ 75,433	$ 86,295
Well Capitalized, Total capital (to risk-weighted assets) Amount	10.00%	10.00%