v3.25.3

Portfolio Loans Receivable and Allowance for Credit Losses - Schedule of Past Due Loans Segregated by Age and Class of Loans (Details) - USD ($) $ in Thousands | Sep. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | $ 2,829,510 | $ 2,637,228
Accruing Loans 90 or More Days Past Due | 6,076 | 1,644
Collected loans | 3,200 |
Nonaccrual Loans | 52,247 | 30,241
Total Past Due Loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 113,690 | 66,768
Loans 30-59 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 40,293 | 25,517
Loans 60-89 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 25,961 | 20,704
Loans 90 or More Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 47,436 | 20,547
Current Loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 2,715,820 | 2,570,460
Commercial and Industrial |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 619,148 | 554,550
Accruing Loans 90 or More Days Past Due | 361 | 0
Nonaccrual Loans | 22,496 | 2,968
Commercial and Industrial | Total Past Due Loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 30,969 | 13,275
Commercial and Industrial | Loans 30-59 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 2,376 | 10,981
Commercial and Industrial | Loans 60-89 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 13,345 | 1,245
Commercial and Industrial | Loans 90 or More Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 15,248 | 1,049
Commercial and Industrial | Current Loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 588,179 | 541,275
Real estate: | Residential |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 740,060 | 688,552
Accruing Loans 90 or More Days Past Due | 615 | 0
Nonaccrual Loans | 6,551 | 8,652
Real estate: | Residential | Total Past Due Loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 19,403 | 13,213
Real estate: | Residential | Loans 30-59 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 9,584 | 1,656
Real estate: | Residential | Loans 60-89 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 2,541 | 4,913
Real estate: | Residential | Loans 90 or More Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 7,278 | 6,644
Real estate: | Residential | Current Loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 720,657 | 675,339
Real estate: | Commercial |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 987,519 | 943,019
Accruing Loans 90 or More Days Past Due | 23 | 100
Nonaccrual Loans | 16,687 | 14,312
Real estate: | Commercial | Total Past Due Loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 34,311 | 19,528
Real estate: | Commercial | Loans 30-59 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 20,590 | 4,957
Real estate: | Commercial | Loans 60-89 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 401 | 7,570
Real estate: | Commercial | Loans 90 or More Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 13,320 | 7,001
Real estate: | Commercial | Current Loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 953,208 | 923,491
Real estate: | Construction |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 344,290 | 321,252
Accruing Loans 90 or More Days Past Due | 3,196 | 0
Nonaccrual Loans | 6,513 | 4,309
Real estate: | Construction | Total Past Due Loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 13,213 | 5,724
Real estate: | Construction | Loans 30-59 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 307 | 1,000
Real estate: | Construction | Loans 60-89 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 3,197 | 415
Real estate: | Construction | Loans 90 or More Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 9,709 | 4,309
Real estate: | Construction | Current Loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 331,077 | 315,528
Credit card, net of reserve | Consumer |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 136,483 | 127,766
Accruing Loans 90 or More Days Past Due | 1,881 | 1,544
Nonaccrual Loans | 0 | 0
Credit card, net of reserve | Consumer | Total Past Due Loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 15,794 | 15,028
Credit card, net of reserve | Consumer | Loans 30-59 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 7,436 | 6,923
Credit card, net of reserve | Consumer | Loans 60-89 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 6,477 | 6,561
Credit card, net of reserve | Consumer | Loans 90 or More Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 1,881 | 1,544
Credit card, net of reserve | Consumer | Current Loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 120,689 | 112,738
Other consumer | Consumer |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 2,010 | 2,089
Accruing Loans 90 or More Days Past Due | 0 | 0
Nonaccrual Loans | 0 | 0
Other consumer | Consumer | Total Past Due Loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 0 | 0
Other consumer | Consumer | Loans 30-59 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 0 | 0
Other consumer | Consumer | Loans 60-89 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 0 | 0
Other consumer | Consumer | Loans 90 or More Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | 0 | 0
Other consumer | Consumer | Current Loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total Portfolio Loans | $ 2,010 | $ 2,089

X
- Definition Financing Receivable, Excluding Accrued Interest, 90 Days Or More Past Due, Still Accruing, Collected + References No definition available. + Details
Name: | cbnk_FinancingReceivableExcludingAccruedInterest90DaysOrMorePastDueStillAccruingCollected
Namespace Prefix: | cbnk_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, of financing receivable 90 days or more past due and still accruing. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 16 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-16 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterest90DaysOrMorePastDueStillAccruing
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-5 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, of financing receivable on nonaccrual status. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 16 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-16 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrual
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_FinancialAssetPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables30To59DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables60To89DaysPastDueMember
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_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancialAssetNotPastDueMember
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: |

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

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

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

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

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