Note 20 - Regulatory Capital (Details) - Regulatory Capital Requirements - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier 1 capital for capital adequacy purposes, ratio	4.50%
Subtotal Bank of Commerce Holdings [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier 1 capital acutal amount	$ 90,743
Common equity tier 1 capital actual ratio	10.06%
Common equity tier 1 capital for capital adequacy purposes amount	$ 40,587
Common equity tier 1 capital for capital adequacy purposes, ratio	4.50%
Common equity tier 1 capital to be well capitalized, amount
Common equity tier 1 capital to be well capitalized, ratio
Tier 1 capital (to risk-weighted assets) actual amount	$ 100,694	$ 113,963
Tier 1 capital (to risk-weighted assets) actual ratio	11.16%	13.91%
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes amount	$ 54,117	$ 32,764
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes ratio	6.00%	4.00%
Tier 1 capital (to risk-weighted assets) to be well capitalized amount
Tier 1 capital (to risk-weighted assets) to be well capitalized ratio
Total capital (to risk-weighted assets) actual amount	$ 121,976	$ 124,217
Total capital (to risk-weighted assets) actual ratio	13.52%	15.16%
Total capital (to risk-weighted assets) for capital adequacy purposes amount	$ 72,155	$ 65,529
Total capital (to risk-weighted assets) for capital adequacy purposes ratio	8.00%	8.00%
Total capital (to risk-weighted assets) to be well capitalized amount
Total capital (to risk-weighted assets) to be well capitalized ratio
Leverage capital (to average assets) actual amount	$ 100,694	$ 113,963
Leverage capital (to average assets) actual ratio	10.03%	11.59%
Leverage capital (to average assets) for capital adequacy purposes amount	$ 40,159	$ 39,328
Leverage capital (to average assets) for capital adequacy purposes ratio	4.00%	4.00%
Leverage capital (to average assets) to be well capitalized amount
Leverage capital (to average assets) to be well capitalized ratio
Commercial Banking [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier 1 capital acutal amount	$ 119,980
Common equity tier 1 capital actual ratio	13.31%
Common equity tier 1 capital for capital adequacy purposes amount	$ 40,570
Common equity tier 1 capital for capital adequacy purposes, ratio	4.50%
Common equity tier 1 capital to be well capitalized, amount	$ 58,601
Common equity tier 1 capital to be well capitalized, ratio	6.50%
Tier 1 capital (to risk-weighted assets) actual amount	$ 119,980	$ 113,640
Tier 1 capital (to risk-weighted assets) actual ratio	13.31%	13.89%
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes amount	$ 54,094	$ 32,734
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes ratio	6.00%	4.00%
Tier 1 capital (to risk-weighted assets) to be well capitalized amount	$ 72,125	$ 49,101
Tier 1 capital (to risk-weighted assets) to be well capitalized ratio	8.00%	8.00%
Total capital (to risk-weighted assets) actual amount	$ 131,257	$ 123,885
Total capital (to risk-weighted assets) actual ratio	14.56%	15.14%
Total capital (to risk-weighted assets) for capital adequacy purposes amount	$ 72,125	$ 65,469
Total capital (to risk-weighted assets) for capital adequacy purposes ratio	8.00%	8.00%
Total capital (to risk-weighted assets) to be well capitalized amount	$ 90,156	$ 81,836
Total capital (to risk-weighted assets) to be well capitalized ratio	10.00%	10.00%
Leverage capital (to average assets) actual amount	$ 119,980	$ 113,640
Leverage capital (to average assets) actual ratio	11.98%	11.57%
Leverage capital (to average assets) for capital adequacy purposes amount	$ 40,067	$ 39,279
Leverage capital (to average assets) for capital adequacy purposes ratio	4.00%	4.00%
Leverage capital (to average assets) to be well capitalized amount	$ 50,084	$ 49,098
Leverage capital (to average assets) to be well capitalized ratio	5.00%	5.00%