Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Jul. 21, 2021
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
Document Transition Report	false
Entity File Number	001-34657
Entity Registrant Name	TEXAS CAPITAL BANCSHARES INC/TX
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	75-2679109
Entity Address, Address Line One	2000 McKinney Avenue
Entity Address, Address Line Two	Suite 700
Entity Address, City or Town	Dallas
Entity Address, State or Province	TX
Entity Address, Country	US
Entity Address, Postal Zip Code	75201
City Area Code	214
Local Phone Number	932-6600
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 Central Index Key	0001077428
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		50,597,797
Common Stock
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	TCBI
Security Exchange Name	NASDAQ
Series B Preferred Stock
Entity Information [Line Items]
Title of 12(b) Security	5.75% Non-Cumulative Perpetual Preferred Stock Series B, par value $0.01 per share
Trading Symbol	TCBIO
Security Exchange Name	NASDAQ