Other Assets - Restricted Investments (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020
Restricted
Investments
Expense for fair value of assets, less expenses, allocated to participants	$ 1.2	$ 1.2

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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