Derivative Financial Instruments (Schedule Of Fair Value Of Derivative Financial Instruments) (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019
Derivative [Line Items]
Derivative assets	$ 327,624	$ 103,644	$ 108,784
Derivative liabilities	355,265	129,204	136,312
Interest Rate Contract
Derivative [Line Items]
Derivative assets	268,709	100,569	104,562
Derivative liabilities	343,519	126,805	131,035
Designated as Hedging Instrument
Derivative [Line Items]
Derivative assets	0	310	1,033
Derivative liabilities	76,625	25,908	27,549
Designated as Hedging Instrument | Interest Rate Contract | Cash Flow Hedging
Derivative [Line Items]
Derivative assets	0	0	616
Derivative liabilities	59,573	19,385	20,851
Designated as Hedging Instrument | Interest Rate Contract | Fair Value Hedging
Derivative [Line Items]
Derivative assets	0	310	417
Derivative liabilities	17,052	6,523	6,698
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative assets	327,624	103,334	107,751
Derivative liabilities	278,640	103,296	108,763
Not Designated as Hedging Instrument | Interest Rate Contract
Derivative [Line Items]
Derivative assets	268,709	100,259	103,529
Derivative liabilities	266,894	100,897	103,486
Not Designated as Hedging Instrument | Interest Rate Lock Commitments
Derivative [Line Items]
Derivative assets	58,841	2,860	4,054
Derivative liabilities	25	259	96
Not Designated as Hedging Instrument | Forward Commitments to Sell Mortgage Loans
Derivative [Line Items]
Derivative assets	27	142	96
Derivative liabilities	11,667	2,070	5,112
Not Designated as Hedging Instrument | Foreign Exchange Contract
Derivative [Line Items]
Derivative assets	47	73	72
Derivative liabilities	$ 54	$ 70	$ 69