Derivative Financial Instruments (Schedule Of Fair Value Of Derivative Financial Instruments) (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Derivative [Line Items]
Derivative assets	$ 138,286	$ 73,172	$ 96,153
Derivative liabilities	171,009	68,088	71,381
Interest Rate Contract
Derivative [Line Items]
Derivative assets	134,386	68,425	91,262
Derivative liabilities	168,897	62,571	69,342
Designated as Hedging Instrument
Derivative [Line Items]
Derivative assets	256	8,906	21,397
Derivative liabilities	34,734	3,412	0
Designated as Hedging Instrument | Interest Rate Contract | Cash Flow Hedging
Derivative [Line Items]
Derivative assets	0	6,270	16,271
Derivative liabilities	25,895	1,656	0
Designated as Hedging Instrument | Interest Rate Contract | Fair Value Hedging
Derivative [Line Items]
Derivative assets	256	2,636	5,126
Derivative liabilities	8,839	1,756	0
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative assets	138,030	64,266	74,756
Derivative liabilities	136,275	64,676	71,381
Not Designated as Hedging Instrument | Interest Rate Contract
Derivative [Line Items]
Derivative assets	134,130	59,519	69,865
Derivative liabilities	134,163	59,159	69,342
Not Designated as Hedging Instrument | Interest Rate Lock Commitments
Derivative [Line Items]
Derivative assets	3,373	3,405	4,128
Derivative liabilities	148	2,694	0
Not Designated as Hedging Instrument | Forward Commitments to Sell Mortgage Loans
Derivative [Line Items]
Derivative assets	176	0	12
Derivative liabilities	1,658	1,486	1,330
Not Designated as Hedging Instrument | Foreign Exchange Contract
Derivative [Line Items]
Derivative assets	351	1,342	751
Derivative liabilities	$ 306	$ 1,337	$ 709