LOANS AND LEASES - Additional Information (Details) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2022 USD ($) state	Dec. 31, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest receivable	$ 54.9	$ 48.9
Discount remaining	$ 37.1	30.0
Number of states, company operating financial services | state	7
Restructured loans returned to performing status	$ 2.5
Total loan on allowance	371.0	344.0
Pooled reserves for all other classes of loans	3.5	3.9
Howard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Discount remaining	$ 10.0
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due period for loan to be in default	90 days
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due period for loan to be in default	12 months
SBA-Guaranteed Loan Servicing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Guaranteed percentage	100.00%
Residential Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value of OREO through foreclosure	$ 1.4	1.6
Mortgage loans on real estate, foreclosure	9.1	4.3
Total commercial loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loan on allowance	275.0	261.2	$ 281.0	$ 280.0
Total commercial loans and leases | Specific Reserves for Commercial Troubled Debt Restructurings
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loan on allowance	1.5	1.5
Total commercial loans and leases | Pooled Reserves For Commercial Troubled Debt Restructurings
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loan on allowance	1.3	1.5
Total commercial loans and leases | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loan on allowance	91.7	87.4	$ 79.0	$ 81.0
Total commercial loans and leases | Commercial and industrial | Paycheck Protection Program Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans to customers	179.6	$ 336.6
Total commercial loans and leases | Commercial loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, collateral dependent	67.3
Total commercial loans and leases | Commercial loan | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Threshold for loans whose terms have been modified in a trouble debt restructuring, non accrual	$ 1.0