XML 87 R65.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Loans (Troubled Debt Restructurings) (Detail) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Financing Receivable, Modifications [Line Items] |  |  |
Balance at Restructure | $ 60,510 | $ 91,418 | $ 709
Balance at Year-end | 58,484 | 44,863 | 536
Commercial Portfolio Segment [Member] |  |  |
Financing Receivable, Modifications [Line Items] |  |  |
Balance at Restructure | 4,026 | 2,148 | 709
Balance at Year-end | 3,766 | 1,022 | 536
Commercial and Industrial, Energy [Member] |  |  |
Financing Receivable, Modifications [Line Items] |  |  |
Balance at Restructure | 56,096 | 87,572 | 0
Balance at Year-end | 54,330 | 43,841 | 0
Commercial Real Estate, Buildings, Land and Other [Member] |  |  |
Financing Receivable, Modifications [Line Items] |  |  |
Balance at Restructure | 0 | 1,455 | 0
Balance at Year-end | 0 | 0 | 0
Construction Loans [Member] |  |  |
Financing Receivable, Modifications [Line Items] |  |  |
Balance at Restructure | 388 | 243 | 0
Balance at Year-end | $ 388 | $ 0 | $ 0

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 Post-modification amount of investment in financing receivables modified by troubled debt restructurings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Pre-modification amount of investment in financing receivables modified by troubled debt restructurings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=84173941&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_CommercialAndIndustrialEnergyFinancingReceivableMember
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: |