Borrowings - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024	Sep. 30, 2024
Long-Term Borrowings
Available capacity	$ 2,723,223	$ 2,674,916
Total additional undrawn borrowing capacity	3,000,000
Long-term line of credit	79,232	88,305
Long-term borrowings	$ 76,428	$ 76,108
Senior notes
Long-Term Borrowings
Interest rates	10.00%	10.00%
Long-term borrowings	$ 76,428	$ 76,108
Unamortized deferred financing costs	1,237	$ 1,557
C D A R S
Long-Term Borrowings
Total additional undrawn borrowing capacity	1,100,000
Long-term line of credit	37,500
I N D
Long-Term Borrowings
Total additional undrawn borrowing capacity	386,000
Federal Reserve Bank of Richmond
Long-Term Borrowings
Total additional undrawn borrowing capacity	1,400,000
Federal Funds
Long-Term Borrowings
Available capacity	145,000
Federal Home Loan Bank
Long-Term Borrowings
FHLB maximum amount available	1,300,000
FHLB amount outstanding at period end	$ 0
Senior Notes, Due September 30, 2029 | Unsecured Debt
Long-Term Borrowings
Interest rates			10.00%
Face amount			$ 77,700