Related Party Transactions - Exchanged Private National Mortgage Acceptance Company, LLC Unitholders (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Transactions with Affiliates
Amount of tax benefits under the tax sharing agreement (as a percent)			85.00%
Payable to exchanged PNMAC unitholders under tax receivable agreement	$ 27.0		$ 27.0		$ 30.5
Private National Mortgage Acceptance Company [Member]
Transactions with Affiliates
Payment of tax liability under the tax receivable agreement to Private National Mortgage Acceptance Company, LLC unitholders	$ 3.5	$ 3.4	$ 3.5	$ 3.4