Advances - Schedule of Activity in Advances (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Advances [Roll Forward]
Advances, beginning balance	$ 686.1	$ 725.1	$ 779.5
New advances	927.5	779.8	784.8
Transfer to Other assets	(8.3)	(14.7)	(6.5)
Sales of advances	(14.2)	(6.3)	(2.9)
Acquisition of advances in connection with the purchase of MSRs	0.8	42.2	0.0
Transfer to Loans held for sale (capitalization upon Ginnie Mae modifications)	(9.3)	(6.4)	(18.1)
Collections of advances and other	(1,014.5)	(863.0)	(824.7)
Advances, ending balance	584.6	686.1	725.1
Advances, net	$ 577.2	$ 678.8	$ 718.9