Short-Term Borrowings and Long-Term Debt - Summary of Long-Term Borrowings (Details) - USD ($) $ in Thousands |
3 Months Ended | 12 Months Ended | ||||
|---|---|---|---|---|---|---|
Jun. 30, 2023 |
Dec. 31, 2023 |
Dec. 31, 2022 |
Dec. 31, 2021 |
May 06, 2021 |
Jan. 31, 2014 |
|
| Schedule Of Borrowings [Line Items] | ||||||
| Long-term debt | $ 859,147 | $ 931,442 | ||||
| Repayments of long-term debt | 75,000 | 0 | $ 111,000 | |||
| Senior Unsecured Credit-Linked Notes, Due 2024 | ||||||
| Schedule Of Borrowings [Line Items] | ||||||
| Senior unsecured credit-linked notes | 199,499 | 272,492 | ||||
| Repayments of long-term debt | $ 75,000 | |||||
| 5.75% Subordinated Notes, Due 2026 | ||||||
| Schedule Of Borrowings [Line Items] | ||||||
| Trust preferred securities issued | 174,457 | 174,196 | ||||
| Interest rate | 5.25% | |||||
| 4.00% Subordinated Notes, Due 2031 | ||||||
| Schedule Of Borrowings [Line Items] | ||||||
| Trust preferred securities issued | 371,785 | 371,348 | ||||
| Interest rate | 4.00% | |||||
| Floating Rate Subordinated Debentures, Due 2032 to 2036 | ||||||
| Schedule Of Borrowings [Line Items] | ||||||
| Trust preferred securities issued | $ 113,406 | $ 113,406 | ||||