Loan Amount Threshold

No definition available.

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- Definition

Loans And Leases Receivable Impaired Average Recorded Investment In Impaired Loans

+ References

No definition available.

+ Details

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- Definition

Loan Value With Weighted-Average Loan-To-Value

+ References

No definition available.

+ Details

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- Definition

Maximum Loan To Value Percentage On Home Equity Loans

+ References

No definition available.

+ Details

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- Definition

Maximum origination value of loans which were subject to further refinement of valuation methodology.

+ References

No definition available.

+ Details

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- Definition

Maximum Percentage of Loan Related To Single Industry

+ References

No definition available.

+ Details

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- Definition

Number Of Days Past Due

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Number Of Loans With Calculated Risk Of Ten Or Higher

+ References

No definition available.

+ Details

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- Definition

Percentage Of Owner Occupied Commercial Real Estate Loans

+ References

No definition available.

+ Details

Name:	cfr_PercentageOfOwnerOccupiedCommercialRealEstateLoans
Namespace Prefix:	cfr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percent Of Valuation Allowance In Excess Of Principal Balance Maximum

+ References

No definition available.

+ Details

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- Definition

Percent Of Valuation Allowance In Excess Of Principal Balance Minimum

+ References

No definition available.

+ Details

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Namespace Prefix:	cfr_
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- Definition

Texas Leading Index economic condition indicator

+ References

No definition available.

+ Details

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- Definition

Weighted Average Loan To Value Ratio Percentage

+ References

No definition available.

+ Details

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- Details

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- Definition

Carrying value as of the balance sheet date of payments made in excess of existing cash balances, which will be honored by the bank but reflected as a loan to the entity. Overdrafts generally have a very short time frame for correction or repayment and are therefore more similar to short-term bank financing than trade financing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 10

-Section 45

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=6743817&loc=d3e1243-112600

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Current Liabilities

-URI http://asc.fasb.org/extlink&oid=6509677

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 43

-Section A

-Paragraph 7

-Chapter 3

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Period Type:	instant

- Definition

Amount of investment in financing receivables (after modification) 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=7512638&loc=SL6953676-111524

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 114

-Paragraph 20

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher OTS

-Name Federal Regulation (FR)

-Number Title 12

-Section 563c.102

-Paragraph 8

-Subparagraph j(ii)

-Chapter V

-Subsection I

-LegacyDoc This is a non-GAAP reference that was included in the 2009 taxonomy. It will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 15

-Paragraph 40

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Balance Type:	credit
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Loans (Narrative) (Detail) (USD $)	12 Months Ended
Loans (Narrative) (Detail) (USD $)	Dec. 31, 2012 Item D	Dec. 31, 2011	Dec. 31, 2010	Nov. 30, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maximum loan-to-value percentage on home equity loans	80.00%
Maximum percentage loan related to single industry	10.00%	10.00%
Commercial and industrial loans related to overdraft for correspondent bank customer	$ 102,400,000	$ 5,200,000
Troubled Debt Restructurings	2,188,000	7,750,000
Average recorded investment in impaired loans			130,800,000
Number of days past due for payment of interest on loans, minimum	120
Number of loans with calculated risk of 10 or higher greater than $5 million	4
Loan amount threshold	5,000,000
Loan value with weighted-average loan-to-value	38,500,000
Weighted-average loan-to-value ratio	65.90%
Texas Leading Index economic condition indicator		120.3		123.0
Maximum origination value of loans which were subject to further refinement of valuation methodology	1,000,000
Commercial And Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and industrial loans related to overdraft for correspondent bank customer	95,300,000
Commercial and Industrial, Other Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings	1,478,000	179,000
Number of days past due for payment of interest on loans, minimum	180
Commercial Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of owner-occupied commercial real estate loans	56.00%
Non-Accrual Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings	2,200,000
Additional interest that would have been recognized on non-accrual loans, net of tax	$ 2,600,000	$ 3,300,000	$ 3,900,000
Grade 12 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
General percentage of valuation allowance in excess of principal balance, maximum	30.00%
Grade 13 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
General percentage of valuation allowance in excess of principal balance, minimum	30.00%