Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Nov. 07, 2019
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2019
Entity File Number	0-15950
Entity Registrant Name	FIRST BUSEY CORPORATION
Entity Incorporation, State or Country Code	NV
Entity Tax Identification Number	37-1078406
Entity Address, Address Line One	100 W. University Ave.
Entity Address, City or Town	Champaign
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	61820
City Area Code	217
Local Phone Number	365-4544
Title of 12(b) Security	Common Stock
Trading Symbol	BUSE
Security Exchange Name	NASDAQ
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		55,047,777
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Entity Central Index Key	0000314489
Amendment Flag	false