Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 21, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	001-15373
Entity Registrant Name	ENTERPRISE FINANCIAL SERVICES CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	43-1706259
Entity Address, Address Line One	150 North Meramec
Entity Address, City or Town	Clayton
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	63105
City Area Code	314
Local Phone Number	725-5500
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	EFSC
Security Exchange Name	NASDAQ
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		26,209,739
Entity Central Index Key	0001025835
Document Period End Date	Sep. 30, 2020
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false