XML 73 R62.htm IDEA: XBRL DOCUMENT
v3.21.2

Loans - Troubled Debt Restructurings (Detail) - USD ($) $ in Thousands | 6 Months Ended
--- | ---
Jun. 30, 2021 | Jun. 30, 2020
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Balance at time of restructuring | $ 4,399 | $ 12,562
Balance at period end | 4,396 | 12,554
Commercial Portfolio Segment [Member] |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Balance at time of restructuring | 0 | 3,660
Balance at period end | 0 | 3,652
Commercial and Industrial Total Energy Loans [Member] |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Balance at time of restructuring | 3,817 | 0
Balance at period end | 3,817 | 0
Commercial real estate, Buildings, land and other [Member] |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Balance at time of restructuring | 582 | 6,606
Balance at period end | 579 | 6,606
Construction Loans [Member] |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Balance at time of restructuring | 0 | 1,192
Balance at period end | 0 | 1,192
Consumer Loan [Member] |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Balance at time of restructuring | 0 | 1,104
Balance at period end | $ 0 | $ 1,104

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 No definition available. + Details
Name: | us-gaap_FinancingReceivableModificationsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, after troubled debt restructuring, of modified financing receivable. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, before troubled debt restructuring, of financing receivable to be modified. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

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

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

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

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