XML 58 R41.htm IDEA: XBRL DOCUMENT
v3.20.4

Off-Balance-Sheet Arrangements, Commitments, Guarantees and Contingencies (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract] |
Financial Instruments With Off-Balance-Sheet Risk | Year-end financial instruments with off-balance-sheet risk were as follows:
| 2020 |  | 2019
Commitments to extend credit | $ | 9,814,475 |  |  | $ | 9,306,043 |
Standby letters of credit | 241,345 |  |  | 260,587 |
Deferred standby letter of credit fees | 1,723 |  |  | 1,276 |
Commitments, Off-Balance-Sheet, Allowance for Credit Losses | The following table details activity in the allowance for credit losses on off-balance-sheet credit exposures.
| 2020 |  | 2019 |  | 2018
Beginning balance | $ | 500 |  |  | $ | 500 |  |  | $ | 428 |
Impact of adopting ASC 326 | 39,377 |  |  | — |  |  | — |
Credit loss expense | 4,275 |  |  | — |  |  | 72 |
Ending balance | $ | 44,152 |  |  | $ | 500 |  |  | $ | 500 |

X
- Definition [Table Text Block] for Commitments, Off-Balance-Sheet, Allowance for Credit Losses [Table] + References No definition available. + Details
Name: | cfr_CommitmentsOffBalanceSheetAllowanceforCreditLossesTableTextBlock
Namespace Prefix: | cfr_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Tabular disclosure of the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined) which are not recognized in the financial statements (off-balance sheet) because they fail to meet some other criterion for recognition. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13467-108611 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611 + Details
Name: | us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration