Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 17, 2020
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		24,851,581
Amendment Flag	false
Entity Central Index Key	0001539638
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
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
Depositary Shares
Document Information [Line Items]
Title of 12(b) Security	Depositary Shares Each Representing a 1/40th Interest in a Share of 7.125% Series C Fixed-Rate Non-Cumulative Perpetual Preferred Stock
Trading Symbol	TBKCP
Security Exchange Name	NASDAQ