Cover - shares	9 Months Ended
	Sep. 30, 2020	Oct. 28, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-37700
Entity Registrant Name	NICOLET BANKSHARES, INC
Entity Incorporation, State or Country Code	WI
Entity Tax Identification Number	47-0871001
Entity Address, Address Line One	111 North Washington Street
Entity Address, City or Town	Green Bay,
Entity Address, State or Province	WI
Entity Address, Postal Zip Code	54301
City Area Code	(920)
Local Phone Number	430-1400
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	NCBS
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		10,085,569
Entity Central Index Key	0001174850
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3