Borrowings (Summary Of Securities Sold Under Agreements To Repurchase And Other Borrowings) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Assets Sold under Agreements to Repurchase [Line Items]
Total Outstanding	$ 1,200,000	$ 1,700,000
Securities sold under agreements to repurchase
Assets Sold under Agreements to Repurchase [Line Items]
Total Outstanding	$ 507,124	$ 469,330
Rate	0.65%	0.43%
Fed funds purchased
Assets Sold under Agreements to Repurchase [Line Items]
Total Outstanding	$ 0	$ 526,025
Rate	0.00%	0.08%
Securities sold under agreements to repurchase and other borrowings
Assets Sold under Agreements to Repurchase [Line Items]
Total Outstanding	$ 507,124	$ 995,355
Rate	0.65%	0.25%
Original maturity of one year or less | Securities sold under agreements to repurchase
Assets Sold under Agreements to Repurchase [Line Items]
Total Outstanding	$ 307,124	$ 269,330
Rate	0.11%	0.13%
Original maturity of greater than one year, non-callable | Securities sold under agreements to repurchase
Assets Sold under Agreements to Repurchase [Line Items]
Total Outstanding	$ 200,000	$ 200,000
Rate	1.47%	0.84%