Financing Receivable, Nonaccrual, Interest Income Reversed

No definition available.

Name:	tcbi_FinancingReceivableNonaccrualInterestIncomeReversed
Namespace Prefix:	tcbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of investment in debt security measured at amortized cost (held-to-maturity), 90 days or more past due and still accruing.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919258-210447

+ Details

Name:	us-gaap_DebtSecuritiesHeldToMaturity90DaysOrMorePastDueStillAccruing
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of interest income on financing receivable on nonaccrual status.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919258-210447

+ Details

Name:	us-gaap_FinancingReceivableNonaccrualInterestIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of financing receivable on nonaccrual status with no allowance for credit loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919258-210447

+ Details

Name:	us-gaap_FinancingReceivableNonaccrualNoAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of financing receivable not past due.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953401-111524

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922355-210448

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919253-210447

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of financing receivable on nonaccrual status.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5111-111524

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919258-210447

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of financing receivable past due.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922355-210448

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919253-210447

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953401-111524

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentPastDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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_FinancingReceivableRecordedInvestmentPastDueLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before allowance for credit loss, of financing receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 79
-URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922352-210448

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919230-210447

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922355-210448

+ Details

Name:	us-gaap_NotesReceivableGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables30To59DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables60To89DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=tcbi_EnergyPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=tcbi_MortgageFinancePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=tcbi_RealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=tcbi_ResidentialHomebuilderFinanceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=tcbi_OtherFinancingReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=tcbi_SecuredByFamilyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Loans Held for Investment and Allowance for Loan Losses - Age Analysis (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 39,754,000
Non-accrual	97,730,000
Current	24,343,217,000
Total	24,480,701,000		$ 24,501,830,000
Non-accrual With No Allowance	43,762,000
Premium finance loans past due and still accruing	3,100,000
Nonaccrual, interest income	0	$ 0
Interest income reversed	339,000
30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	30,662,000
60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,905,000
Greater Than 90 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	6,187,000
Commercial
Financing Receivable, Past Due [Line Items]
Total Past Due	22,353,000
Non-accrual	38,194,000
Current	8,908,677,000
Total	8,969,224,000		8,861,580,000
Non-accrual With No Allowance	15,860,000
Commercial \| 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	15,563,000
Commercial \| 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,905,000
Commercial \| Greater Than 90 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	3,885,000
Energy
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Non-accrual	29,368,000
Current	662,438,000
Total	691,806,000		766,217,000
Non-accrual With No Allowance	18,189,000
Energy \| 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Energy \| 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Energy \| Greater Than 90 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Mortgage finance
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Non-accrual	0
Current	9,009,081,000
Total	9,009,081,000		9,079,409,000
Non-accrual With No Allowance	0
Mortgage finance \| 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Mortgage finance \| 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Mortgage finance \| Greater Than 90 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Real estate
Financing Receivable, Past Due [Line Items]
Total	5,810,590,000		$ 5,794,624,000
Real estate \| Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Total Past Due	17,177,000
Non-accrual	6,696,000
Current	3,665,119,000
Total	3,688,992,000
Non-accrual With No Allowance	1,849,000
Real estate \| Residential Homebuilder Finance
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Non-accrual	0
Current	895,680,000
Total	895,680,000
Non-accrual With No Allowance	0
Real estate \| Other Financing Receivable
Financing Receivable, Past Due [Line Items]
Total Past Due	105,000
Non-accrual	23,254,000
Current	867,524,000
Total	890,883,000
Non-accrual With No Allowance	7,864,000
Real estate \| Secured by 1-4 family
Financing Receivable, Past Due [Line Items]
Total Past Due	119,000
Non-accrual	218,000
Current	334,698,000
Total	335,035,000
Non-accrual With No Allowance	0
Real estate \| 30 to 59 Days Past Due \| Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Total Past Due	14,939,000
Real estate \| 30 to 59 Days Past Due \| Residential Homebuilder Finance
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Real estate \| 30 to 59 Days Past Due \| Other Financing Receivable
Financing Receivable, Past Due [Line Items]
Total Past Due	105,000
Real estate \| 30 to 59 Days Past Due \| Secured by 1-4 family
Financing Receivable, Past Due [Line Items]
Total Past Due	55,000
Real estate \| 60 to 89 Days Past Due \| Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Real estate \| 60 to 89 Days Past Due \| Residential Homebuilder Finance
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Real estate \| 60 to 89 Days Past Due \| Other Financing Receivable
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Real estate \| 60 to 89 Days Past Due \| Secured by 1-4 family
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Real estate \| Greater Than 90 Days \| Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Total Past Due	2,238,000
Real estate \| Greater Than 90 Days \| Residential Homebuilder Finance
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Real estate \| Greater Than 90 Days \| Other Financing Receivable
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Real estate \| Greater Than 90 Days \| Secured by 1-4 family
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 64,000