Cover Page - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Feb. 09, 2021	Jun. 30, 2020
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-36722
Entity Registrant Name	TRIUMPH BANCORP, INC.
Entity Incorporation, State or Country Code	TX
Entity Tax Identification Number	20-0477066
Entity Address, Address Line One	12700 Park Central Drive, Suite 1700
Entity Address, City or Town	Dallas
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75251
City Area Code	214)
Local Phone Number	365-6900
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 536,944
Entity Common Stock, Shares Outstanding		24,878,009
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0001539638
Documents Incorporated by Reference	Portions of the Registrant’s Definitive Proxy Statement relating to the Annual Meeting of Stockholders, which will be filed within 120 days after December 31, 2020, are incorporated by reference into Part III of this Report.
Common Stock
Document Information [Line Items]
Title of 12(b) Security	Common Stock, Par Value $0.01 Per Share
Trading Symbol	TBK
Security Exchange Name	NASDAQ
Series C Preferred Stock
Document Information [Line Items]
Title of 12(b) Security	7.125% Series C Fixed-Rate Non-Cumulative Perpetual Preferred Stock
Trading Symbol	TBKCP
Security Exchange Name	NASDAQ