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Acquisitions and Discontinued Operations (Details) - USD ($) $ in Millions			12 Months Ended
	May 02, 2022	Nov. 19, 2021	Dec. 31, 2022	Dec. 31, 2023
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill acquired			$ 58.0
Discontinued operations \| Government Guaranteed Loans \| Government-guaranteed and Private Education Lending Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loans included in divestiture			$ 434.0	$ 339.0
XUP
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill acquired		$ 20.6
GradFin
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill acquired	$ 58.0
Business combination, consideration transferred	72.0
Cash payment	62.0
Contingent consideration	10.0
Intangible assets acquired	$ 12.0