XML 62 R51.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Securities Securities - Sales of Securities Held to Maturity (Details) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2017 | Mar. 31, 2016
Investment, Debt and Equity Securities [Abstract] |  |
Proceeds from Sale of Held to Maturity Securities | $ 0 | $ 135,610
Held to maturity securities sold amortized cost | 0 | 131,840
Held-to-maturity Securities, Sold Security, Realized Gain (Loss) | 0 | 3,770
Held to maturity securities sold security gross realized loss | 0 | 0
Tax (expense) benefit of held to maturity securities gains/losses | $ 0 | $ (1,319)

X
- Definition Held to maturity securities sold amortized cost + References No definition available. + Details
Name: | cfr_Heldtomaturitysecuritiessoldamortizedcost
Namespace Prefix: | cfr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Held to maturity securities sold security gross realized loss + References No definition available. + Details
Name: | cfr_Heldtomaturitysecuritiessoldsecuritygrossrealizedloss
Namespace Prefix: | cfr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Investment, Debt and Equity Securities [Abstract] + References No definition available. + Details
Name: | cfr_InvestmentDebtandEquitySecuritiesAbstract
Namespace Prefix: | cfr_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tax expense held to maturity security gains + References No definition available. + Details
Name: | cfr_TaxExpenseHeldToMaturitySecurityGains
Namespace Prefix: | cfr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition This item represents the gain (loss) realized on the sale of held-to-maturity securities disposed of during the period. Additionally, this item may include, if not separately presented, any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt securities which are being or have been recognized in earnings during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27405-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesSoldSecurityRealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash inflow associated with the sale of securities that had been designated as held-to-maturity. Excludes proceeds from maturities, prepayments and calls by the issuer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26853-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfHeldToMaturitySecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration