OTHER BORROWINGS - Schedule of Terms of Outstanding Junior Subordinated Debentures (Details) - Trust Preferred Securities - Junior Subordinated Debentures	9 Months Ended
	Sep. 30, 2026 USD ($)
Debt Instrument [Line Items]
Issuance Amount	$ 198,499,000
Bridgeview Statutory Trust I
Debt Instrument [Line Items]
Issuance Amount	$ 15,464,000
Variable rate	3.58%
Rate	7.66%
Bridgeview Capital Trust II
Debt Instrument [Line Items]
Issuance Amount	$ 15,464,000
Variable rate	3.35%
Rate	7.36%
First Midwest Capital Trust I
Debt Instrument [Line Items]
Issuance Amount	$ 37,825,000
Fixed rate	6.95%
Rate	6.95%
St. Joseph Capital Trust II
Debt Instrument [Line Items]
Issuance Amount	$ 5,155,000
Variable rate	1.75%
Rate	5.99%
Northern States Statutory Trust I
Debt Instrument [Line Items]
Issuance Amount	$ 10,310,000
Variable rate	1.80%
Rate	5.96%
Anchor Capital Trust III
Debt Instrument [Line Items]
Issuance Amount	$ 5,000,000
Variable rate	1.55%
Rate	5.89%
Great Lakes Statutory Trust II
Debt Instrument [Line Items]
Issuance Amount	$ 6,186,000
Variable rate	1.40%
Rate	5.56%
Bremer Statutory Trust II
Debt Instrument [Line Items]
Issuance Amount	$ 61,856,000
Variable rate	1.60%
Rate	5.62%
Home Federal Statutory Trust I
Debt Instrument [Line Items]
Issuance Amount	$ 15,464,000
Variable rate	1.65%
Rate	5.81%
Monroe Bancorp Capital Trust I
Debt Instrument [Line Items]
Issuance Amount	$ 3,093,000
Variable rate	1.60%
Rate	5.61%
Tower Capital Trust 3
Debt Instrument [Line Items]
Issuance Amount	$ 9,279,000
Variable rate	1.69%
Rate	5.71%
Monroe Bancorp Statutory Trust II
Debt Instrument [Line Items]
Issuance Amount	$ 5,155,000
Variable rate	1.60%
Rate	5.76%
Great Lakes Statutory Trust III
Debt Instrument [Line Items]
Issuance Amount	$ 8,248,000
Variable rate	1.70%
Rate	5.86%