XML 90 R79.htm IDEA: XBRL DOCUMENT
v3.24.3

Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands | Sep. 30, 2024 | Dec. 31, 2023
--- | --- | ---
Derivative [Line Items] |  |
Weighted-average strike rate for outstanding interest rate caps | 3.64% |
Approximate credit exposure related to swaps with bank customers | $ 30,100 |
Interest rate swaps with upstream financial institution counterparties [Member] |  |
Derivative [Line Items] |  |
Approximate credit exposure related to swaps with bank customers | 2,700 |
Not Designated as Hedging Instrument [Member] | Financial Institution Counterparties Loan Lease Interest Rate Swaps Liabilities [Member] |  |
Derivative [Line Items] |  |
Estimated fair value of derivative contracts cleared through Chicago Mercantile Exchange | $ 0 | $ 0

X
- Definition Estimated fair value of derivative contracts cleared through Chicago Mercantile Exchange + References No definition available. + Details
Name: | cfr_EstimatedfairvalueofderivativecontractsclearedthroughChicagoMercantileExchange
Namespace Prefix: | cfr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Weighted Average Strike Rate Outstanding Interest Rate Caps + References No definition available. + Details
Name: | cfr_WeightedAverageStrikeRateOutstandingInterestRateCaps
Namespace Prefix: | cfr_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Maximum potential amount of future undiscounted payments that could be required under the credit derivative, before reduction for potential recoveries under recourse or collateralization provisions. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4K -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4K + Details
Name: | us-gaap_CreditDerivativeMaximumExposureUndiscounted
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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/disclosureRef -Topic 815 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480237/815-40-50-5 + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=cfr_InterestRateSwapsWithUpstreamFinancialInstitutionCounterpartiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=cfr_FinancialInstitutionCounterpartiesLoanLeaseInterestRateSwapsLiabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |