XML 66 R41.htm IDEA: XBRL DOCUMENT v2.4.1.9
Loans and Allowance for Loan Losses (Evaluation for Impairment) (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Mar. 31, 2014
Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]        
ALL, individually evaluated for impairment $ 364us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1 $ 418us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1    
ALL, collectively evaluated for impairment 15,450us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment 16,690us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment    
ALL, PI loans evaluated for credit impairment 3,194us-gaap_FinancingReceivableAllowanceForCreditLossesAcquiredWithDeterioratedCreditQuality 3,237us-gaap_FinancingReceivableAllowanceForCreditLossesAcquiredWithDeterioratedCreditQuality    
ALL, PI loans with no credit deterioration 0cob_FinancingReceivableAllowanceForCreditLossesAcquiredWithNoCreditDeterioration 0cob_FinancingReceivableAllowanceForCreditLossesAcquiredWithNoCreditDeterioration    
Total ALL evaluated for impairment 19,008us-gaap_FinancingReceivableAllowanceForCreditLosses 20,345us-gaap_FinancingReceivableAllowanceForCreditLosses 26,039us-gaap_FinancingReceivableAllowanceForCreditLosses 26,785us-gaap_FinancingReceivableAllowanceForCreditLosses
Loans held for investment, individually evaluated for impairment 29,689us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment 34,482us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment    
Loans held for investment, collectively evaluated for impairment 1,256,960us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment 1,200,464us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment    
Loans held for investment, PI loans with subsequent credit deterioration 105,662us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality 118,701us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality    
Loans held for investment, PI loans with no credit deterioration 3,600cob_FinancingReceivableAcquiredWithNoCreditDeterioration 4,141cob_FinancingReceivableAcquiredWithNoCreditDeterioration    
Loans held for investment 1,395,911us-gaap_LoansAndLeasesReceivableGrossCarryingAmount 1,357,788us-gaap_LoansAndLeasesReceivableGrossCarryingAmount [1]    
Commercial and agricultural [Member]        
Financing Receivable, Allowance for Credit Losses [Line Items]        
ALL, individually evaluated for impairment 0us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		 58us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		    
ALL, collectively evaluated for impairment 3,159us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		 3,600us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		    
ALL, PI loans evaluated for credit impairment 239us-gaap_FinancingReceivableAllowanceForCreditLossesAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		 257us-gaap_FinancingReceivableAllowanceForCreditLossesAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		    
ALL, PI loans with no credit deterioration 0cob_FinancingReceivableAllowanceForCreditLossesAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		 0cob_FinancingReceivableAllowanceForCreditLossesAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		    
Total ALL evaluated for impairment 3,398us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		 3,915us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		 3,441us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		 2,931us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember
Loans held for investment, individually evaluated for impairment 444us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		 498us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		    
Loans held for investment, collectively evaluated for impairment 108,348us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		 105,380us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		    
Loans held for investment, PI loans with subsequent credit deterioration 6,841us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		 7,535us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		    
Loans held for investment, PI loans with no credit deterioration 0cob_FinancingReceivableAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		 0cob_FinancingReceivableAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		    
Loans held for investment 115,633us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		 113,413us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_CommercialAndAgriculturalPortfolioSegmentMember		    
Real estate - construction [Member]        
Financing Receivable, Allowance for Credit Losses [Line Items]        
ALL, individually evaluated for impairment 0us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		 0us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		    
ALL, collectively evaluated for impairment 2,337us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		 2,656us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		    
ALL, PI loans evaluated for credit impairment 783us-gaap_FinancingReceivableAllowanceForCreditLossesAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		 507us-gaap_FinancingReceivableAllowanceForCreditLossesAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		    
ALL, PI loans with no credit deterioration 0cob_FinancingReceivableAllowanceForCreditLossesAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		 0cob_FinancingReceivableAllowanceForCreditLossesAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		    
Total ALL evaluated for impairment 3,120us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		 3,163us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		 5,308us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		 5,233us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember
Loans held for investment, individually evaluated for impairment 1,262us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		 2,344us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		    
Loans held for investment, collectively evaluated for impairment 72,808us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		 66,786us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		    
Loans held for investment, PI loans with subsequent credit deterioration 8,112us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		 8,619us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		    
Loans held for investment, PI loans with no credit deterioration 543cob_FinancingReceivableAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		 578cob_FinancingReceivableAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		    
Loans held for investment 82,725us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		 78,327us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= cob_RealEstateConstructionPortfolioSegmentMember		    
Real estate - mortgage, 1-4 family residential [Member]        
Financing Receivable, Allowance for Credit Losses [Line Items]        
ALL, individually evaluated for impairment 353us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 331us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		    
ALL, collectively evaluated for impairment 5,030us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 5,317us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		    
ALL, PI loans evaluated for credit impairment 240us-gaap_FinancingReceivableAllowanceForCreditLossesAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 199us-gaap_FinancingReceivableAllowanceForCreditLossesAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		    
ALL, PI loans with no credit deterioration 0cob_FinancingReceivableAllowanceForCreditLossesAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 0cob_FinancingReceivableAllowanceForCreditLossesAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		    
Total ALL evaluated for impairment 5,623us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 5,847us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 7,923us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 8,869us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
Loans held for investment, individually evaluated for impairment 11,596us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 11,409us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		    
Loans held for investment, collectively evaluated for impairment 648,184us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 638,456us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		    
Loans held for investment, PI loans with subsequent credit deterioration 13,272us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 14,174us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		    
Loans held for investment, PI loans with no credit deterioration 3,057cob_FinancingReceivableAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 3,563cob_FinancingReceivableAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		    
Loans held for investment 676,109us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 667,602us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		    
Real estate - mortgage, commercial [Member]        
Financing Receivable, Allowance for Credit Losses [Line Items]        
ALL, individually evaluated for impairment 11us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 29us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		    
ALL, collectively evaluated for impairment 1,397us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 2,065us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		    
ALL, PI loans evaluated for credit impairment 1,744us-gaap_FinancingReceivableAllowanceForCreditLossesAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 2,085us-gaap_FinancingReceivableAllowanceForCreditLossesAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		    
ALL, PI loans with no credit deterioration 0cob_FinancingReceivableAllowanceForCreditLossesAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 0cob_FinancingReceivableAllowanceForCreditLossesAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		    
Total ALL evaluated for impairment 3,152us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 4,179us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 6,966us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 7,195us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Loans held for investment, individually evaluated for impairment 16,387us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 20,231us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		    
Loans held for investment, collectively evaluated for impairment 345,229us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 318,752us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		    
Loans held for investment, PI loans with subsequent credit deterioration 76,489us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 87,345us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		    
Loans held for investment, PI loans with no credit deterioration 0cob_FinancingReceivableAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 0cob_FinancingReceivableAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		    
Loans held for investment 438,105us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 426,328us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		    
Consumer [Member]        
Financing Receivable, Allowance for Credit Losses [Line Items]        
ALL, individually evaluated for impairment 0us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 0us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		    
ALL, collectively evaluated for impairment 3,527us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 3,052us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		    
ALL, PI loans evaluated for credit impairment 188us-gaap_FinancingReceivableAllowanceForCreditLossesAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 189us-gaap_FinancingReceivableAllowanceForCreditLossesAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		    
ALL, PI loans with no credit deterioration 0cob_FinancingReceivableAllowanceForCreditLossesAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 0cob_FinancingReceivableAllowanceForCreditLossesAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		    
Total ALL evaluated for impairment 3,715us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 3,241us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 2,401us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 2,557us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Loans held for investment, individually evaluated for impairment 0us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 0us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		    
Loans held for investment, collectively evaluated for impairment 82,391us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 71,090us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		    
Loans held for investment, PI loans with subsequent credit deterioration 948us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 1,028us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		    
Loans held for investment, PI loans with no credit deterioration 0cob_FinancingReceivableAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 0cob_FinancingReceivableAcquiredWithNoCreditDeterioration
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		    
Loans held for investment $ 83,339us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 $ 72,118us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		    
[1] Derived from audited consolidated financial statements