Related Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Related Party
Related Party Transaction [Line Items]
Management fee expense	$ 1.8	$ 1.9	$ 2.0
Accounts payable	$ 1.0	$ 1.0
Wellington Management Company LLP
Related Party Transaction [Line Items]
Ownership percentage by noncontrolling owners	5.00%	5.00%
BlackRock Financial Management Inc.
Related Party Transaction [Line Items]
Ownership percentage by noncontrolling owners	5.00%	5.00%

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business.

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Amount of expense for investment management fee, including, but not limited to, expense in connection with research, selection, supervision, and custody of investment.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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