Loans and Allowance for Credit Losses on Loans - Loans by Investment Grade (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	$ 2,957,285	$ 2,305,541
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	1,880,868	2,161,134
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	1,717,252	3,438,876
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	2,469,728	1,314,739
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	719,332	334,555
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	888,143	1,055,959
Revolving lines of credit	13,498,964	11,901,022
Revolving lines of credit converted to term loans	15,430	30,997
Total	24,147,002	22,542,823
Financing receivable, excluding accrued interest, year one, originated, current fiscal year, writeoff	11,233	994
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year, writeoff	704	7,543
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year, writeoff	4,234	550
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year, writeoff	8,958	4,037
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year, writeoff	28	537
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year, writeoff	2,011	8,784
Revolving lines of credit, writeoff	25,715	23,566
Revolving line of credit converted to term loans, writeoff	0	44
Financing receivable, excluding accrued interest, allowance for credit loss, writeoff	52,883	46,055
Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	2,136,305	1,636,271
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	1,204,095	1,238,889
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	743,398	1,450,224
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	758,778	337,071
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	159,843	77,512
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	162,620	203,360
Revolving lines of credit	7,078,407	6,190,224
Revolving lines of credit converted to term loans	9,359	12,040
Total	12,252,805	11,145,591
Financing receivable, excluding accrued interest, allowance for credit loss, writeoff	51,428	37,761
Commercial \| Pass
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	2,091,840	1,612,695
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	1,179,067	1,156,414
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	679,840	1,256,539
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	679,947	307,590
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	109,856	76,821
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	145,550	169,974
Revolving lines of credit	6,977,639	6,027,177
Revolving lines of credit converted to term loans	9,359	12,040
Total	11,873,098	10,619,250
Commercial \| Special mention
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	7,659	22,953
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	16,204	28,354
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	16,093	134,092
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	42,441	21,626
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	15,346	30
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	1,239	6,369
Revolving lines of credit	39,073	91,423
Revolving lines of credit converted to term loans	0	0
Total	138,055	304,847
Commercial \| Substandard - accruing
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	25,513	623
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	8,824	44,901
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	44,506	51,536
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	0	7,855
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	34,641	301
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	4,192	3,309
Revolving lines of credit	27,830	37,405
Revolving lines of credit converted to term loans	0	0
Total	145,506	145,930
Commercial \| Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	11,293	0
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	0	9,220
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	2,959	8,057
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	36,390	0
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	0	360
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	11,639	23,708
Revolving lines of credit	33,865	34,219
Revolving lines of credit converted to term loans	0	0
Total	96,146	75,564
Mortgage finance
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	0	0
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	0	0
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	0	0
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	0	0
Revolving lines of credit	6,064,019	5,215,574
Revolving lines of credit converted to term loans	0	0
Total	6,064,019	5,215,574
Financing receivable, excluding accrued interest, allowance for credit loss, writeoff	0	0
Mortgage finance \| Pass
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	0	0
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	0	0
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	0	0
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	0	0
Revolving lines of credit	6,064,019	5,215,574
Revolving lines of credit converted to term loans	0	0
Total	6,064,019	5,215,574
Mortgage finance \| Special mention
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	0	0
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	0	0
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	0	0
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	0	0
Revolving lines of credit	0	0
Revolving lines of credit converted to term loans	0	0
Total	0	0
Mortgage finance \| Substandard - accruing
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	0	0
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	0	0
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	0	0
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	0	0
Revolving lines of credit	0	0
Revolving lines of credit converted to term loans	0	0
Total	0	0
Mortgage finance \| Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	0	0
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	0	0
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	0	0
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	0	0
Revolving lines of credit	0	0
Revolving lines of credit converted to term loans	0	0
Total	0	0
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	784,422	624,918
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	638,866	893,956
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	945,631	1,934,504
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	1,660,110	901,744
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	486,457	216,376
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	611,916	752,164
Revolving lines of credit	262,280	273,663
Revolving lines of credit converted to term loans	6,071	18,957
Total	5,395,753	5,616,282
Financing receivable, excluding accrued interest, allowance for credit loss, writeoff	1,455	8,264
Commercial real estate \| Pass
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	783,669	599,301
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	567,849	889,603
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	944,903	1,843,706
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	1,548,624	885,913
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	425,325	216,077
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	610,386	704,288
Revolving lines of credit	254,480	273,663
Revolving lines of credit converted to term loans	5,305	18,085
Total	5,140,541	5,430,636
Commercial real estate \| Special mention
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	743	25,532
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	45,137	4,353
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	728	70,161
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	90,752	15,831
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	61,132	299
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	1,530	13,731
Revolving lines of credit	7,800	0
Revolving lines of credit converted to term loans	766	872
Total	208,588	130,779
Commercial real estate \| Substandard - accruing
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	10	0
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	25,880	0
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	0	0
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	0	20,230
Revolving lines of credit	0	0
Revolving lines of credit converted to term loans	0	0
Total	25,890	20,230
Commercial real estate \| Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	0	85
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	0	0
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	0	20,637
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	20,734	0
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	0	0
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	0	13,915
Revolving lines of credit	0	0
Revolving lines of credit converted to term loans	0	0
Total	20,734	34,637
Consumer
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	36,558	44,352
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	37,907	28,289
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	28,223	54,148
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	50,840	75,924
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	73,032	40,667
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	113,607	100,435
Revolving lines of credit	94,258	221,561
Revolving lines of credit converted to term loans	0	0
Total	434,425	565,376
Financing receivable, excluding accrued interest, allowance for credit loss, writeoff	0	30
Consumer \| Pass
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	36,558	44,352
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	37,907	28,289
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	28,223	54,148
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	50,840	75,924
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	73,032	40,667
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	113,607	99,471
Revolving lines of credit	94,258	220,561
Revolving lines of credit converted to term loans	0	0
Total	434,425	563,412
Consumer \| Special mention
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	0	0
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	0	0
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	0	0
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	0	0
Revolving lines of credit	0	0
Revolving lines of credit converted to term loans	0	0
Total	0	0
Consumer \| Substandard - accruing
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	0	0
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	0	0
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	0	0
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	0	0
Revolving lines of credit	0	1,000
Revolving lines of credit converted to term loans	0	0
Total	0	1,000
Consumer \| Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, excluding accrued interest, year one, originated, current fiscal year	0	0
Financing receivable, excluding accrued interest, year two, originated, fiscal year before current fiscal year	0	0
Financing receivable, excluding accrued interest, year three, originated, two years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year four, originated, three years before current fiscal year	0	0
Financing receivable, excluding accrued interest, year five, originated, four years before current fiscal year	0	0
Financing receivable, excluding accrued interest, originated, more than five years before current fiscal year	0	964
Revolving lines of credit	0	0
Revolving lines of credit converted to term loans	0	0
Total	$ 0	$ 964

Financing Receivable, Excluding Accrued Interest, Revolving, Converted To Term Loans

No definition available.

Name:	tcbi_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoans
Namespace Prefix:	tcbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-6

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-5

+ Details

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

- Definition

Amortized cost excluding accrued interest, of financing receivable originated more than five years prior to current fiscal year. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 79
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-79

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-6

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B

+ Details

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

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated more than five years before current fiscal year. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-6

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amortized cost excluding accrued interest, of financing receivable that can be withdrawn, repaid, and redrawn.

+ References

+ Details

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

- Definition

Amount, excluding accrued interest, of writeoff of revolving financing receivable converted to term loan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-6A

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoanWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable that can be withdrawn, repaid, and redrawn.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amortized cost excluding accrued interest, of financing receivable originated four years prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

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

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated four years before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amortized cost excluding accrued interest, of financing receivable originated three years prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

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

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated three years before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amortized cost excluding accrued interest, of financing receivable originated in current fiscal year. Excludes net investment in lease.

+ References

+ Details

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

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated in current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amortized cost excluding accrued interest, of financing receivable originated two years prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

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

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated two years before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amortized cost excluding accrued interest of financing receivable originated in fiscal year prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

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

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated in fiscal year before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (d)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (d)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (d)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (d)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 8: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-15

Reference 10: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-5

Reference 11: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-15

Reference 12: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 13: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 14: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (e)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 15: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (e)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 16: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (b)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 17: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (b)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 18: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 19: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-15

Reference 20: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-15

Reference 21: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-15

Reference 22: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 29
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-29

Reference 23: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 79
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-79

+ Details

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

- Details

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

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_PassMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_SpecialMentionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_SubstandardMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=tcbi_NonAccrualMember
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=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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