Borrowings (Summary Of Securities Sold Under Agreements To Repurchase And Other Borrowings) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	$ 710,967	$ 740,526
Fed funds purchased	161,725	209,000
Securities sold under agreements to repurchase and other borrowings	$ 872,692	$ 949,526
Securities Sold under Agreements to Repurchase [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	1.79%	1.82%
Federal Funds Purchased [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	1.13%	0.46%
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	1.66%	1.53%
Original maturity of one year or less [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	$ 310,967	$ 340,526
Original maturity of one year or less [Member] | Securities Sold under Agreements to Repurchase [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	0.17%	0.16%
Original maturity of greater than one year, non-callable [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	$ 400,000	$ 400,000
Original maturity of greater than one year, non-callable [Member] | Securities Sold under Agreements to Repurchase [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	3.04%	3.09%