Borrowings (Narrative) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Jan. 31, 2022
Assets Sold under Agreements to Repurchase [Line Items]
Notes and subordinated debt	$ 1,039,651	$ 1,059,778
Sterling
Assets Sold under Agreements to Repurchase [Line Items]
Long-term debt			$ 516,881
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%