Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 28, 2020	Jun. 28, 2019
Entity Information [Line Items]
Document Type	10-K/A
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
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 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 Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Public Float			$ 3,070,019,000
Entity Common Stock, Shares Outstanding		50,397,277
Entity Central Index Key	0001077428
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	FY
Amendment Flag	true
Common Stock [Member]
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 A Preferred Stock [Member]
Entity Information [Line Items]
Title of 12(b) Security	6.5% Non-Cumulative Perpetual Preferred Stock Series A, par value $0.01 per share
Trading Symbol	TCBIP
Security Exchange Name	NASDAQ