Shareholders Equity and Regulatory Matters - Schedule of comparison of the actual capital amounts and ratios (Details) $ in Thousands	Jun. 30, 2026 USD ($)	Dec. 31, 2025 USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital (to risk weighted assets), Actual, Amount	$ 742,032	$ 628,120
Total capital (to risk weighted assets), Actual, Ratio	0.1201	0.1248
Total capital (to risk weighted assets), For Capital Adequacy Purposes, Amount	$ 648,544	$ 528,317
Total capital (to risk weighted assets), For Capital Adequacy Purposes, Ratio	0.105	0.105
Tier 1 capital (to risk weighted assets), Actual, Amount	$ 610,697	$ 501,426
Tier 1 capital (to risk weighted assets), Actual, Ratio	0.0989	0.0997
Tier 1 capital (to risk weighted assets), For Capital Adequacy Purposes, Amount	$ 525,011	$ 427,686
Tier 1 capital (to risk weighted assets), For Capital Adequacy Purposes, Ratio	0.085	0.085
Tier 1 capital (to average assets), Actual, Amount	$ 610,697	$ 501,426
Tier 1 capital (to average assets), Actual, Ratio	0.0935	0.0965
Tier 1 capital (to average assets), For Capital Adequacy Purposes, Amount	$ 261,335	$ 207,886
Tier 1 capital (to average assets), For Capital Adequacy Purposes, Ratio	0.04	0.04
Common equity tier 1 (to risk weighted assets), Actual, Amount	$ 544,537	$ 435,266
Common equity tier 1 (to risk weighted assets), Actual, Ratio	0.0882	0.0865
Common equity tier 1 (to risk weighted assets), For Capital Adequacy Purposes, Amount	$ 432,362	$ 352,212
Common equity tier 1 (to risk weighted assets), For Capital Adequacy Purposes, Ratio	0.07	0.07
THIRD COAST BANK
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital (to risk weighted assets), Actual, Amount	$ 796,834	$ 660,607
Total capital (to risk weighted assets), Actual, Ratio	0.1291	0.1314
Total capital (to risk weighted assets), For Capital Adequacy Purposes, Amount	$ 647,846	$ 527,767
Total capital (to risk weighted assets), For Capital Adequacy Purposes, Ratio	0.105	0.105
Total capital (to risk weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 616,996	$ 502,636
Total capital (to risk weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.10	0.10
Tier 1 capital (to risk weighted assets), Actual, Amount	$ 746,567	$ 614,878
Tier 1 capital (to risk weighted assets), Actual, Ratio	0.121	0.1223
Tier 1 capital (to risk weighted assets), For Capital Adequacy Purposes, Amount	$ 524,447	$ 427,240
Tier 1 capital (to risk weighted assets), For Capital Adequacy Purposes, Ratio	0.085	0.085
Tier 1 capital (to risk weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 493,597	$ 402,108
Tier 1 capital (to risk weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.08	0.08
Tier 1 capital (to average assets), Actual, Amount	$ 746,567	$ 614,878
Tier 1 capital (to average assets), Actual, Ratio	0.1144	0.1184
Tier 1 capital (to average assets), For Capital Adequacy Purposes, Amount	$ 261,101	$ 207,672
Tier 1 capital (to average assets), For Capital Adequacy Purposes, Ratio	0.04	0.04
Tier 1 capital (to average assets), To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 326,376	$ 259,591
Tier 1 capital (to average assets), To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.05	0.05
Common equity tier 1 (to risk weighted assets), Actual, Amount	$ 746,567	$ 614,878
Common equity tier 1 (to risk weighted assets), Actual, Ratio	0.121	0.1223
Common equity tier 1 (to risk weighted assets), For Capital Adequacy Purposes, Amount	$ 431,897	$ 351,845
Common equity tier 1 (to risk weighted assets), For Capital Adequacy Purposes, Ratio	0.07	0.07
Common equity tier 1 (to risk weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 401,047	$ 326,713
Common equity tier 1 (to risk weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.065	0.065

Tier one risk based capital required for capital adequacy with buffer.

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Ratio of minimum Common Equity Tier 1 risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
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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.

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