Borrowings (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets Sold under Agreements to Repurchase [Line Items]
Notes and subordinated debt	$ 903,086	$ 1,036,974
Debt issuance cost on senior fixed-rates	(1,337)	(1,419)
Long-term debt	914,520	1,048,820
Subordinated Debt
Assets Sold under Agreements to Repurchase [Line Items]
Premium on subordinated fixed-to-floating rate notes	13,269	13,802
Senior Notes
Assets Sold under Agreements to Repurchase [Line Items]
Debt Instrument, Unamortized Discount	(498)	(537)
Junior subordinated debt
Assets Sold under Agreements to Repurchase [Line Items]
Notes and subordinated debt	77,320	77,320
Subordinated Notes Due 2029 | Subordinated Debt
Assets Sold under Agreements to Repurchase [Line Items]
Notes and subordinated debt	$ 274,000	274,000
Senior notes, interest rate (as a percent)	4.00%
Subordinated Notes Due 2030 | Subordinated Debt
Assets Sold under Agreements to Repurchase [Line Items]
Notes and subordinated debt	$ 225,000	225,000
Senior notes, interest rate (as a percent)	3.875%
Senior Notes | Senior Notes
Assets Sold under Agreements to Repurchase [Line Items]
Notes and subordinated debt	$ 0
Senior Notes Due 2024 | Senior Notes
Assets Sold under Agreements to Repurchase [Line Items]
Notes and subordinated debt		132,550
Senior notes, interest rate (as a percent)	4.375%
Senior Notes Due 2029 | Senior Notes
Assets Sold under Agreements to Repurchase [Line Items]
Notes and subordinated debt	$ 326,766	$ 328,104
Senior notes, interest rate (as a percent)	4.10%