PARENT COMPANY ONLY FINANCIAL INFORMATION - Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Assets
Cash and due from subsidiary	$ 121,211	$ 209,349
Total assets	8,763,969	7,695,037
Liabilities and Stockholders’ Equity
Other liabilities	70,177	68,729
Stockholders’ equity	972,529	891,891
Total liabilities and stockholders’ equity	8,763,969	7,695,037
Nicolet Bankshares, Inc
Assets
Cash and due from subsidiary	63,927	84,656
Investments	10,313	9,684
Investments in subsidiaries	1,094,063	998,032
Other assets	392	1,503
Total assets	1,168,695	1,093,875
Liabilities and Stockholders’ Equity
Junior subordinated debentures	39,720	38,885
Subordinated notes	152,622	153,030
Other liabilities	3,824	10,069
Stockholders’ equity	972,529	891,891
Total liabilities and stockholders’ equity	$ 1,168,695	$ 1,093,875