| **Fair Values of Assets and Liabilities** | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        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| **Fair Value Disclosures [Abstract]**     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              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| Fair Values of Assets and Liabilities     | Fair Values of Assets and LiabilitiesWe use fair value measurements to record fair value adjustments to certain assets and liabilities and to determine fair value disclosures.  Securities available-for-sale, derivative assets and liabilities, mortgage loans held for sale, and mortgage servicing rights are recorded at fair value on a recurring basis.  Additionally, from time-to-time, we may be required to record at fair value other assets and liabilities on a nonrecurring basis, such as loans held for investment, impaired loans and certain other assets and liabilities.  These nonrecurring fair value adjustments typically involve application of lower of cost or market accounting or write-downs of individual assets or liabilities.Fair Value HierarchyWe group assets and liabilities at fair value in three levels, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value.  These levels are:Level 1:  Valuation is based upon quoted prices for identical instruments traded in active markets.Level 2:  Valuation is based upon quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable in the market.Level 3:  Valuation is generated from model-based techniques that use at least one significant assumption not observable in the market.  These unobservable assumptions reflect estimates of assumptions that market participants would use in pricing the asset or liability.  Valuation techniques include use of option pricing models, discounted cash flow models and similar techniques.Disclosure of fair value information about financial instruments, whether or not recognized in the balance sheet, for which it is practicable to estimate that value, is required.  Fair value estimates are made at a specific point in time, based on relevant market information and information about the financial instrument.  These estimates do not reflect any premium or discount that could result from offering for sale at one time our entire holdings of a particular financial instrument.Because no market exists for a portion of our financial instruments, fair value estimates are based on judgments regarding future expected losses, current economic conditions, risk characteristics of various financial instruments, and other factors.  These estimates are subjective in nature and involve uncertainties and matters of significant judgment and, therefore, cannot be determined with precision.  Changes in assumptions could significantly affect the estimates.The following is a description of valuation methodologies used for assets and liabilities recorded at fair value:Investments Securities Available-for-SaleInvestment securities available-for-sale are recorded at fair value on a recurring basis.  Fair value measurement is based upon quoted prices, if available.  If quoted prices are not available, fair values are measured using independent pricing models or other model-based valuation techniques such as the present value of future cash flows, adjusted for the security's credit rating, prepayment assumptions and other factors such as credit loss assumptions.  Level 1 securities include those traded on an active exchange, such as the New York Stock Exchange, U.S. Treasury securities that are traded by dealers or brokers in active over-the-counter markets and money market funds.  Level 2 securities include mortgage-backed securities issued by government sponsored entities, municipal bonds and corporate debt securities.  Securities classified as Level 3 may include asset-backed securities in less liquid markets.Liquidity is a significant factor in the determination of the fair values of available-for-sale debt securities.  Market price quotes may not be readily available for some positions, or positions within a market sector where trading activity has slowed significantly or ceased.  Some of these instruments are valued using a discounted cash flow model, which estimates the fair value of the securities using internal credit risk, interest rate and prepayment risk models that incorporate management's best estimate of current key assumptions such as default rates, loss severity and prepayment rates.  Principal and interest cash flows are discounted using an observable discount rate for similar instruments with adjustments that management believes a market participant would consider in determining fair value for the specific security.  Underlying assets are valued using external pricing services, where available, or matrix pricing based on the vintages and ratings.  Situations of illiquidity generally are triggered by the market's perception of credit uncertainty regarding a single company or a specific market sector.  In these instances, fair value is determined based on limited available market information and other factors, principally from reviewing the issuer's financial statements and changes in credit ratings made by one or more ratings agencies.Loans Held for SaleLoans held for sale are carried at the lower of cost or fair value less estimated costs to sell. Once sold, the purchasing investor has all rights of ownership, including the ability to pledge or exchange the loans. Most of the loans sold are without recourse.  However, the investor does have the ability to require CommunityOne to repurchase or indemnify a specific loan should there be inadequacies discovered in the original underwriting of that loan. Gains or losses on loan sales are recognized at the time of sale, are determined by the difference between net sales proceeds and the carrying value of the loan sold, and are included in Consolidated Statements of Operations. Since loans held for sale are carried at the lower of cost or fair value, the fair value of loans held for sale is based on contractual agreements with independent third party buyers. As such, we classify loans held for sale subjected to nonrecurring fair value adjustments as Level 2.  Based on the nature of the portfolio, lack of market volatility and the short duration for which the loans are held, fair value generally exceeds cost.Loans Held for InvestmentWe do not record loans held for investment at fair value on a recurring basis.  However, from time to time, a loan is considered impaired and the related impairment is charged against the allowance or a specific allowance is established.  Loans for which it is probable that payment of interest and principal will not be made in accordance with the contractual terms of the loan agreement are considered impaired.  Once a loan is identified as impaired, we determine the fair value of the loan to quantify impairment, should such exist.  The fair value of impaired loans is estimated using one of several methods, including collateral net liquidation value, market value of similar debt, enterprise value, and discounted cash flows.  Those impaired loans not requiring a specific allowance represent loans for which the fair value of the expected repayments or collateral meet or exceed the recorded investments in such loans.  At March 31, 2016 and December 31, 2015, substantially all of the total impaired loans were reviewed based on the fair value of the collateral.  Impaired loans where an allowance is established based on the fair value of collateral require classification in the fair value hierarchy.  We record impaired loans as nonrecurring Level 3.Other Real Estate OwnedOREO is adjusted to fair value upon transfer of the loans to OREO.  Subsequently, OREO is carried at the lower of carrying value or fair value less estimated costs to sell.  Fair value is based upon independent market prices, appraised values of the collateral or management's estimation of the value of the collateral.  Given the lack of observable market prices for identical properties, we record OREO as nonrecurring Level 3.Interest Rate Locks and Forward Loan Sale CommitmentsWe enter into interest rate lock commitments and commitments to sell mortgages. The fair value of interest rate lock commitments is based on servicing rate premium, origination income net of origination costs, fall out rates and changes in loan pricing between the commitment date and the balance sheet date.  We record interest rate lock commitments as recurring level 3, and based on their immaterial value, has excluded them from the fair value table.Interest Rate SwapsWe enter into interest rate swaps to hedge the variability of interest cash flow payments on certain FHLB advances.  Changes in fair value of these cash flow hedges are recorded through other comprehensive income.  Any ineffectiveness of the hedge is included in current period earnings.  The fair value of our interest rate swaps is based on a third party valuation because there is not a readily available quoted price in the market.  We record interest rate swap commitments as recurring level 2.Mortgage Servicing RightsThe fair value of mortgage serving rights ("MSR") is dependent upon a number of assumptions including the fee per loan, the cost to service, the expected loan prepayment rate, and the discount rate.  In determining the fair value of the existing MSR management reviews the key assumptions, analyzes pricing in the market for comparable MSR, and uses a third party provider to independently calculate the fair value of its MSR.  We record mortgage servicing rights as recurring Level 3.Assets and Liabilities Recorded at Fair Value on a Recurring BasisAssets and liabilities carried at fair value on a recurring basis at March 31, 2016 are summarized in the following table:(dollars in thousands) Total Level 1 Level 2 Level 3Assets:        Available-for-sale debt securities:        U.S. government sponsored agencies $— $— $— $—Residential mortgage-backed securities-GSE 277,062 — 277,062 —Residential mortgage-backed securities-Private 31,434 — 31,434 —Commercial mortgage-backed securities-GSE 22,122 — 22,122 —Commercial mortgage-backed securities-Private 17,848 — 17,848 —Corporate notes 37,528 — 37,528 —Total available-for-sale debt securities 385,994 — 385,994 —Mortgage servicing rights 2,654 — — 2,654Interest rate swaps (1,627) — (1,627) —Total assets at fair value $387,021 $— $384,367 $2,654Assets and liabilities carried at fair value on a recurring basis at December 31, 2015 are summarized in the following table:(dollars in thousands) Total Level 1 Level 2 Level 3Assets:        Available-for-sale debt securities:        U.S. government sponsored agencies $2,008 $— $2,008 $—Residential mortgage-backed securities-GSE 278,107 — 278,107 —Residential mortgage-backed securities-Private 33,577 — 33,577 —Commercial mortgage-backed securities-GSE 21,611 — 21,611 —Commercial mortgage-backed securities-Private 17,575 — 17,575 —Corporate notes 37,555 — 37,555 —Total available-for-sale debt securities 390,433 — 390,433 —Mortgage servicing rights 2,231 — — 2,231Interest rate swaps (755) — (755) —Total assets at fair value $391,909 $— $389,678 $2,231The following table presents a reconciliation of all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the periods indicated:  Fair Value Measurements Using Significant  Unobservable Inputs (Level 3)  Mortgage Servicing Rights(dollars in thousands) Three Months Ended March 31,  2016 2015Balance, beginning of period $2,231 $1,726Total gains or losses (realized/unrealized):    Included in earnings, gross 593 300      Less amortization (170) (130)Balance, end of period $2,654 $1,896     Assets and Liabilities Recorded at Fair Value on a Nonrecurring BasisWe may be required, from time to time, to measure certain assets at fair value on a nonrecurring basis in accordance with U.S. generally accepted accounting principles.  These include assets that are measured at the lower of cost or market that were recognized at fair value below cost at the end of the period.  This is due to further deterioration in the value of the assets. There were no loans held for sale that had a fair value below cost in any periods reported.Assets measured at fair value on a nonrecurring basis are included in the following table at March 31, 2016:(dollars in thousands) Total Level 1 Level 2 Level 3Impaired loans, net $2,364 $— $— $2,364Other real estate owned 7,159 — — 7,159Total assets at fair value from continuing operations $9,523 $— $— $9,523Assets measured at fair value on a nonrecurring basis are included in the following table at December 31, 2015:(dollars in thousands) Total Level 1 Level 2 Level 3Impaired loans, net $3,418 $— $— $3,418Other real estate owned 10,630 — — 10,630Total assets at fair value from continuing operations $14,048 $— $— $14,048Quantitative Information about Level 3 Fair Value Measurements(dollars in thousands) Fair Value at March 31, 2016 Valuation Techniques UnobservableInput Range        Impaired loans, net $2,364 Discounted appraisals Collateral discounts 1.00% - 30.00%Other real estate owned 7,159 Discounted appraisals Collateral discounts 1.00% - 30.00%Mortgage servicing rights 2,654 Discounted cash flows Prepayment rate 10.00% - 25.00%Mortgage servicing rights     Discount rate 6.00% - 10.00%(dollars in thousands) Fair Value atDecember 31, 2015 Valuation Techniques UnobservableInput Range         Impaired loans, net $3,418 Discounted appraisals Collateral discounts 1.00%-30.00%Other real estate owned 10,630 Discounted appraisals Collateral discounts 1.00%-30.00%Mortgage servicing rights 2,231 Discounted cash flows Prepayment rate 10.00% - 25.00%Mortgage servicing rights     Discount rate 6.00% - 10.00%Fair Value of Financial InstrumentsThe following methods and assumptions were used to estimate the fair value for each class of COB's financial instruments.Cash and cash equivalents.Fair value equals the carrying value of such assets due to their nature and is classified as Level 1.Investment securities.    The fair value of investment securities is based on quoted market prices, if available.  If a quoted market price is not available, fair value is estimated using quoted market prices for similar securities. The fair value of equity investments in the restricted stock of the FRBR and FHLB approximates the carrying value. The fair value of investment securities is classified as Level 1 if a quoted market price is available, or Level 2 if a quoted market price is not available.Loans held for sale.  Substantially all residential mortgage loans held for sale are pre-sold and their carrying value approximates fair value.  We classified the fair value of loans held for sale as Level 2.Loans held for investment.  The fair value of loans is estimated by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities.  We classified the fair value of loans as Level 3.Accrued interest receivable and payable.  The carrying amounts of accrued interest payable and receivable approximate fair value and are classified as Level 1, 2 or 3 based on whether the related asset or liability is classified as Level 1, 2 or 3.Deposits.   The fair value of noninterest-bearing and interest-bearing demand deposits and savings are the amounts payable on demand because these products have no stated maturity.  The fair value of time deposits is estimated using the rates currently offered for deposits of similar remaining maturities and are classified as Level 2.Borrowed funds.  The carrying value of retail repurchase agreements is considered to be a reasonable estimate of fair value.  The fair value of FHLB advances and other borrowed funds is estimated using the rates currently offered for advances of similar remaining maturities and is classified as Level 2.  For the long-term note payable, the current market rate for similar debt is substantially equal to the rate on this note, so its fair value approximates its carrying value.Junior subordinated debentures.  Included in junior subordinated debentures are variable rate trust preferred securities issued by COB.  Fair values for the trust preferred securities were estimated by developing cash flow estimates for each of these debt instruments based on scheduled principal and interest payments and current interest rates.  Once the cash flows were determined, a rate for comparable subordinated debt was used to discount the cash flows to the present value. We classified the fair value of junior subordinated debentures as Level 3.Financial instruments with off-balance sheet risk.   The fair value of financial instruments with off-balance sheet risk is considered to approximate carrying value, since the large majority of these future financing commitments would result in loans that have variable rates and/or relatively short terms to maturity.  For other commitments, generally of a short-term nature, the carrying value is considered to be a reasonable estimate of fair value.Interest rate swaps.  The fair value of interest rate swaps are measured based on third party cash flow models discounted to the valuation date and are classified as Level 2.Interest rate locks and forward loan sale commitments.  The fair value of interest rate locks and forward loan sale commitments are measured by comparing the underlying terms of the contract with current pricing obtained from broker dealer pricing and are classified as Level 2.The estimated fair values of financial instruments are as follows at the periods indicated:  At March 31, 2016(dollars in thousands) Carrying Value Estimated Fair Value Level 1 Level 2 Level 3Financial Assets:          Cash and cash equivalents $63,578 $63,578 $63,578 $— $—Investment securities:  Available-for-sale 385,994 385,994 — 385,994 —Investment securities:  Held-to-maturity 145,127 145,853 — 145,853 —Loans held for sale 4,328 4,328 — 4,328 —Loans held for investment, net 1,510,166 1,512,307 — — 1,512,307Accrued interest receivable 5,421 5,421 3 1,522 3,896Interest rate swaps (1,627) (1,627) — (1,627) —Financial Liabilities:          Deposits 1,955,190 1,956,107 — 1,956,107 —Retail repurchase agreements 7,352 7,352 — 7,352 —Federal Home Loan Bank advances 65,167 67,437 — 67,437 —Long-term notes payable 5,435 5,435 — — 5,435Junior subordinated debentures 56,702 31,853 — — 31,853Accrued interest payable 387 387 — 368 19  At December 31, 2015(dollars in thousands) Carrying Value Estimated Fair Value Level 1 Level 2 Level 3Financial Assets:          Cash and cash equivalents $39,175 $39,175 $39,175 $— $—Investment securities:  Available-for-sale 390,434 390,434 — 390,434 —Investment securities:  Held-to-maturity 147,967 145,184 — 145,184 —Loans held for sale 5,403 5,403 — 5,403 —Loans held for investment, net 1,528,600 1,513,226 — — 1,513,226Accrued interest receivable 5,305 5,305 — 1,630 3,675Interest rate locks and forward loan sale commitments (755) (755) — (755) —Financial Liabilities:          Deposits 1,947,537 1,945,691 — 1,945,691 —Retail repurchase agreements 7,219 7,219 — 7,219 —Federal Home Loan Bank advances 93,681 95,781 — 95,781 —Long-term notes payable 5,415 5,415 — — 5,415Junior subordinated debentures 56,702 32,536 — — 32,536Accrued interest payable 367 367 — 349 18There were no transfers between valuation levels for any assets during the three months ended March 31, 2016. If different valuation techniques are deemed necessary, we would consider those transfers to occur at the end of the period when the assets are valued. |

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| - References
No definition available.
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| - Definition
Tabular disclosure of the fair value measurement of liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and gains or losses recognized in other comprehensive income (loss) and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs) by class of liability.
+ References
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