Loans Held for Sale - Summary of Activity in Balance of Loans Held for Sale, at Lower of Cost or Fair Value (Footnote) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Ginnie Mae
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale, at lower of cost or fair value	$ 60.6	$ 51.8	$ 19.6

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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