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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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Percentage of vesting of share-based compensation awards.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The highest quantity of shares an employee can purchase under the plan per period.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Gross number of share options (or share units) granted during the period.

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The addition or reduction in the number of reserved shares that could potentially be issued under the option plan attributable to reasons other than grants, exercises, forfeitures, and expirations during the reporting period.

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The number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date.

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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Number of share options (or share units) exercised during the current period.

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Shareholders' Equity (Share-based Compensation - Narrative) (Details) (USD $)	12 Months Ended			0 Months Ended		1 Months Ended
	Dec. 31, 2014 director plan	Dec. 31, 2013 plan	Dec. 31, 2012 plan	Oct. 21, 2011	Dec. 28, 2012	Dec. 31, 2012	Dec. 31, 2006 plan	Jun. 20, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share-based compensation plans	5cob_NumberOfShareBasedCompensationPlans	5cob_NumberOfShareBasedCompensationPlans	5cob_NumberOfShareBasedCompensationPlans			5cob_NumberOfShareBasedCompensationPlans
Share-based compensation expense	$ 853,000	$ 628,000	$ 3,000
Share-based compensation expense related income tax benefit	326,000	250,000	1,000
Number of non-executive directors	9cob_NumberofNonExecutiveDirectors
Stock options granted (in shares)	255,227	54,060	0
Stock options exercised, intrinsic value	0	0	0
Stock options vested, grant date fair value	46,000	0	0
Stock options exercised (in shares)	0	0	0
Unrecognized compensation cost related to non-vested share-based compensation arrangements	1,800,000
Granite Corp. [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options assumed from acquisition (in shares)				78
Stock options exercisable (in shares)	0
Integrity Financial Corporation [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share-based compensation plans							3
Number of shares available for grants	0
Restricted stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	223,503	158,302
Awards cancelled (in shares)	267,937	0
Awards vested, fair value	$ 323,000	$ 0	$ 1,000
Restricted stock [Member] \| Officers and Directors [Member] \| First Anniversary of Grant Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	25.00%
Restricted stock [Member] \| Officers and Directors [Member] \| Second Anniversary of Grant Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	25.00%
Restricted stock [Member] \| Officers and Directors [Member] \| Third Anniversary of Grant Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	25.00%
Restricted stock [Member] \| Officers and Directors [Member] \| Fourth Anniversary of Grant Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	25.00%
Restricted stock [Member] \| Officer [Member] \| Second Anniversary of Grant Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage		66.67%
Restricted stock [Member] \| Officer [Member] \| Third Anniversary of Grant Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage		33.33%
Restricted stock [Member] \| Officer [Member] \| Later of Lifting of Consent Orders or Second Anniversary of Date of Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			66.67%
Restricted stock [Member] \| Officer [Member] \| Later of Lifting of Consent Orders or Third Anniversary of Date of Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			33.33%
Restricted stock [Member] \| Director [Member] \| First Anniversary of Grant Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage		33.33%
Restricted stock [Member] \| Director [Member] \| Second Anniversary of Grant Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage		33.33%
Restricted stock [Member] \| Director [Member] \| Third Anniversary of Grant Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage		33.33%
Restricted stock [Member] \| Employees [Member] \| First Anniversary of Grant Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	25.00%	25.00%
Restricted stock [Member] \| Employees [Member] \| Second Anniversary of Grant Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	25.00%	25.00%
Restricted stock [Member] \| Employees [Member] \| Third Anniversary of Grant Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	25.00%	25.00%
Restricted stock [Member] \| Employees [Member] \| Fourth Anniversary of Grant Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	25.00%	25.00%
Stock Options [Member]
Black-Scholes option pricing model, fair value assumptions:
Expected volatility, period of historical volatility			6 years
Expected life of options	6 years
2012 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance								1,800,000
Maximum number of shares of COB common stock each employee may be granted during any calendar year period	100,000
2012 Incentive Plan [Member] \| Restricted stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	223,503	158,302			110,059	110,059
Number of individuals granted awards			6
Awards cancelled (in shares)	269,946
2012 Incentive Plan [Member] \| Restricted stock [Member] \| Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of individuals granted awards	6					6
2012 Incentive Plan [Member] \| Restricted stock [Member] \| Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of individuals granted awards	8
Stock Compensation Plan 1993 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grants	0
Stock Compensation Plan 1993 [Member] \| Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award become exercisable period	1 year
Award vesting period	5 years
Stock Compensation Plan 1993 [Member] \| Stock Options [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award expiration period	10 years
2003 stock compensation plan [Member] \| Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award become exercisable period	1 year
Award vesting period	5 years
2003 stock compensation plan [Member] \| Stock Options [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award expiration period	10 years