v3.25.3

Portfolio Loans Receivable and Allowance for Credit Losses - Schedule of Loan Modifications Past Due (Details) $ in Thousands | Sep. 30, 2025 USD ($)
--- | ---
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | $ 3,962
Nonaccrual | 890
Current Loans |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 3,072
Past Due 30-89 Days |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 0
Loans 90 or More Days Past Due |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 0
Residential | Real estate: |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 44
Nonaccrual | 0
Residential | Real estate: | Current Loans |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 44
Residential | Real estate: | Past Due 30-89 Days |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 0
Residential | Real estate: | Loans 90 or More Days Past Due |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 0
Residential | Residential - Home Equity |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 0
Nonaccrual | 0
Residential | Residential - Home Equity | Current Loans |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 0
Residential | Residential - Home Equity | Past Due 30-89 Days |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 0
Residential | Residential - Home Equity | Loans 90 or More Days Past Due |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 0
Commercial | Real estate: |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 1,414
Nonaccrual | 890
Commercial | Real estate: | Current Loans |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 524
Commercial | Real estate: | Past Due 30-89 Days |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 0
Commercial | Real estate: | Loans 90 or More Days Past Due |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 0
Commercial and Industrial |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 2,504
Nonaccrual | 0
Commercial and Industrial | Current Loans |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 2,504
Commercial and Industrial | Past Due 30-89 Days |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | 0
Commercial and Industrial | Loans 90 or More Days Past Due |
Financing Receivable, Past Due [Line Items] |
Total loans modified in last twelve months | $ 0

X
- Definition Financing Receivable, Excluding Accrued Interest, Modified, After 12 Months, Nonaccrual + References No definition available. + Details
Name: | cbnk_FinancingReceivableExcludingAccruedInterestModifiedAfter12MonthsNonaccrual
Namespace Prefix: | cbnk_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, of financing receivable 12 months after modification for debtor experiencing financial difficulty. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 42 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-42 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestModifiedPast12Months
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (d)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 5: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (d)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 6: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (d)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (d)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 8: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 9: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 10: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 11: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 14 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-14 Reference 12: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (e)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 13: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (e)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 14: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (b)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 15: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (b)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 16: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-12 Reference 17: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 80 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-80 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancialAssetNotPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=cbnk_FinancialAsset30To89DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_RealEstateLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=cbnk_CommercialAndIndustrialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |