Loans and Allowance for Credit Losses - Loan Modifications (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Receivables [Abstract]
Total modifications	$ 0	$ 10,459

Amount of loans modified during the period with payment deferrals granted in accordance with the CARES Act and regulatory guidance.

No definition available.

Name:	tbk_FinancingReceivablesPaymentDeferralModificationsModifiedDuringPeriod
Namespace Prefix:	tbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration