CONTRACTUAL COMMITMENTS, CONTINGENCIES, AND OFF-BALANCE SHEET ARRANGEMENTS - Additional Information (Details) $ in Millions	12 Months Ended
Jun. 30, 2026 USD ($)
Contractual Commitments Contingencies And Off- Balance Sheet Arrangements [Line Items]
Unconsolidated investment	$ 24.4
Future commitment to fund	20.2
Estimate of possible loss	5.0
Other Future Minimum Commitments
Contractual Commitments Contingencies And Off- Balance Sheet Arrangements [Line Items]
Other liabilities	128.5
Information Technology Services Agreement
Contractual Commitments Contingencies And Off- Balance Sheet Arrangements [Line Items]
Remaining commitment amount under agreement	385.1
SIS Services Agreement
Contractual Commitments Contingencies And Off- Balance Sheet Arrangements [Line Items]
Remaining commitment amount under agreement	103.1
IBM Private Cloud Agreement
Contractual Commitments Contingencies And Off- Balance Sheet Arrangements [Line Items]
Remaining commitment amount under agreement	62.9
A W S Cloud Agreement
Contractual Commitments Contingencies And Off- Balance Sheet Arrangements [Line Items]
Remaining commitment amount under agreement	$ 23.8

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