v3.26.1
Borrowings - Financing VIEs (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Debt Outstanding      
Short-Term $ 0 $ 498,415  
Long-Term 5,844,116 5,362,494  
Total 5,844,116 5,860,909  
Carrying Amount of Net Assets Securing Debt Outstanding      
Restricted Cash 206,858 177,263 $ 163,761
Other Assets, Net 43,304 47,315  
Total assets 28,579,411 29,746,295  
Variable Interest Entity, Primary Beneficiary      
Debt Outstanding      
Short-Term 0 0  
Long-Term 4,855,994 4,869,079  
Total 4,855,994 4,869,079  
Carrying Amount of Net Assets Securing Debt Outstanding      
Loans 6,220,983 6,249,064  
Restricted Cash 174,852 177,260  
Other Assets, Net 401,067 378,997  
Total assets 6,796,902 6,805,321  
Variable Interest Entity, Primary Beneficiary | Private Education Loan term securitizations      
Debt Outstanding      
Short-Term 0 0  
Long-Term 4,855,994 4,869,079  
Total 4,855,994 4,869,079  
Carrying Amount of Net Assets Securing Debt Outstanding      
Loans 6,220,983 6,249,064  
Restricted Cash 174,852 177,260  
Other Assets, Net 401,067 377,673  
Total assets 6,796,902 6,803,997  
Variable Interest Entity, Primary Beneficiary | Secured Borrowing Facility      
Debt Outstanding      
Short-Term 0 0  
Long-Term 0 0  
Total 0 0  
Carrying Amount of Net Assets Securing Debt Outstanding      
Loans 0 0  
Restricted Cash 0 0  
Other Assets, Net 0 1,324  
Total assets $ 0 $ 1,324