Short-Term Borrowings and Long-Term Debt - Summary of Long-Term Borrowings (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	May 06, 2021	Jan. 31, 2014
Schedule Of Borrowings [Line Items]
Long-term debt	$ 932,119	$ 931,442
Senior Unsecured Credit-Linked Notes, Due 2024
Schedule Of Borrowings [Line Items]
Senior unsecured credit-linked notes	272,994	272,492
5.75% Subordinated Notes, Due 2026
Schedule Of Borrowings [Line Items]
Trust preferred securities issued	174,262	174,196
Interest rate				5.25%
4.00% Subordinated Notes, Due 2031
Schedule Of Borrowings [Line Items]
Trust preferred securities issued	371,457	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