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Variable Interest Entities - Narrative (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Variable Interest Entity [Line Items]
Percentage of outstanding equity interests	50.00%
Maximum exposure to trusts			$ 36.4
Reimbursement obligation coverage percentage			12.00%
MW Advisor, LLC
Variable Interest Entity [Line Items]
Ownership percentage	50.00%
Marathon Direct Lending SLP, LLC
Variable Interest Entity [Line Items]
Ownership percentage	50.00%
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Deposits assumed	$ 99.1	$ 212.0
Non-marketable investment carrying value	237.2		$ 216.5
Variable Interest Entity, Not Primary Beneficiary \| Unfunded Loan Commitment
Variable Interest Entity [Line Items]
Maximum exposure to loss	$ 352.7		$ 332.8