| **Capital Matters (Tables)**                    | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
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| **Regulatory Capital Requirements [Abstract]**  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| Compliance with Regulatory Capital Requirements | Quantitative measures established by regulation to ensure capital adequacy require each bank to maintain minimum amounts and ratios (set forth in the accompanying table) of total and Tier 1 capital (as defined in the regulations) to risk-weighted assets (as defined), and of Tier 1 capital to average assets (as defined). The minimum capital requirements to be characterized as “well-capitalized” and “adequately capitalized,” as defined by the prompt corrective action provision of federal law and CommunityOne’s  capital ratios as of December 31, 2014 are noted in the following table.  At December 31, 2014, CommunityOne Bank was designated as “well capitalized.”       Minimum Regulatory Requirement to be Well Capitalized(dollars in thousands) Actual For CapitalAdequacy Purposes Under PromptCorrective ActionProvisions   Amount Ratio Amount Ratio Amount Ratio December 31, 2014                Total Capital (to Risk Weighted Assets)                Consolidated $203,150 14.58% $110,982   8.00% N/A    CommunityOne Bank, N.A. 206,474 14.88 111,013   8.00 $138,767  10.00% Tier 1 Capital (to Risk Weighted Assets)                Consolidated 185,690 13.33 55,491   N/A N/A    CommunityOne Bank, N.A. 189,081 13.63 55,507   4.00 83,260  6.00 Tier 1 Capital (to Average Assets)                Consolidated 185,690 9.78 $75,937   N/A N/A    CommunityOne Bank, N.A. 189,081 9.94 76,068   4.00 95,085  5.00                  December 31, 2013                Total Capital (to Risk Weighted Assets)                Consolidated $159,146 12.62% $100,859   8.00% N/A    CommunityOne Bank, N.A. 166,152 13.20 100,713   8.00 125,891  10.00 Tier 1 Capital (to Risk Weighted Assets)                Consolidated 119,499 9.48 50,429   N/A N/A    CommunityOne Bank, N.A. 150,274 11.94 50,356   4.00 75,534  6.00 Tier 1 Capital (to Average Assets)                Consolidated 119,499 5.96 80,220   N/A N/A    CommunityOne Bank, N.A. 150,274 7.49 80,204   4.00 100,256  5.00  |

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| - Definition
Tabular disclosure of the capital amounts and ratios as of the balance sheet date, indicating whether the entity or entities are in compliance with regulatory capital requirements, by entity.
+ References
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