LOANS AND LEASES - Schedule of Loan Modifications, Aging Analysis (Details) - USD ($) $ in Millions	Mar. 31, 2025	Mar. 31, 2024
Current
Financing Receivable, Modified [Line Items]
Total	$ 48.0	$ 41.3
30-89 Days Past Due
Financing Receivable, Modified [Line Items]
Total	2.2	1.5
90+ Days Past Due
Financing Receivable, Modified [Line Items]
Total	0.4	1.0
Total commercial loans and leases | Current
Financing Receivable, Modified [Line Items]
Total	39.0	34.9
Total commercial loans and leases | 30-89 Days Past Due
Financing Receivable, Modified [Line Items]
Total	0.0	0.0
Total commercial loans and leases | 90+ Days Past Due
Financing Receivable, Modified [Line Items]
Total	0.0	0.0
Total commercial loans and leases | Commercial real estate | Current
Financing Receivable, Modified [Line Items]
Total	20.2	14.9
Total commercial loans and leases | Commercial real estate | 30-89 Days Past Due
Financing Receivable, Modified [Line Items]
Total	0.0	0.0
Total commercial loans and leases | Commercial real estate | 90+ Days Past Due
Financing Receivable, Modified [Line Items]
Total	0.0	0.0
Total commercial loans and leases | Commercial and industrial | Current
Financing Receivable, Modified [Line Items]
Total	18.8	20.0
Total commercial loans and leases | Commercial and industrial | 30-89 Days Past Due
Financing Receivable, Modified [Line Items]
Total	0.0	0.0
Total commercial loans and leases | Commercial and industrial | 90+ Days Past Due
Financing Receivable, Modified [Line Items]
Total	0.0	0.0
Total consumer loans | Current
Financing Receivable, Modified [Line Items]
Total	9.0	6.4
Total consumer loans | 30-89 Days Past Due
Financing Receivable, Modified [Line Items]
Total	2.2	1.5
Total consumer loans | 90+ Days Past Due
Financing Receivable, Modified [Line Items]
Total	0.4	1.0
Total consumer loans | Direct installment | Current
Financing Receivable, Modified [Line Items]
Total	1.2	2.0
Total consumer loans | Direct installment | 30-89 Days Past Due
Financing Receivable, Modified [Line Items]
Total	0.0	0.0
Total consumer loans | Direct installment | 90+ Days Past Due
Financing Receivable, Modified [Line Items]
Total	0.0	0.2
Total consumer loans | Residential mortgages | Current
Financing Receivable, Modified [Line Items]
Total	7.0	3.1
Total consumer loans | Residential mortgages | 30-89 Days Past Due
Financing Receivable, Modified [Line Items]
Total	2.0	1.1
Total consumer loans | Residential mortgages | 90+ Days Past Due
Financing Receivable, Modified [Line Items]
Total	0.4	0.8
Total consumer loans | Consumer lines of credit | Current
Financing Receivable, Modified [Line Items]
Total	0.8	1.3
Total consumer loans | Consumer lines of credit | 30-89 Days Past Due
Financing Receivable, Modified [Line Items]
Total	0.2	0.4
Total consumer loans | Consumer lines of credit | 90+ Days Past Due
Financing Receivable, Modified [Line Items]
Total	$ 0.0	$ 0.0