Derivative Financial Instruments (Schedule Of Fair Value Of Derivative Financial Instruments) (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Derivative [Line Items]
Derivative assets	$ 75,504	$ 73,172	$ 78,960
Derivative liabilities	73,868	68,088	55,699
Interest Rate Contract
Derivative [Line Items]
Derivative assets	68,317	68,425	72,970
Derivative liabilities	69,292	62,571	52,443
Designated as Hedging Instrument
Derivative [Line Items]
Derivative assets	4,613	8,906	19,974
Derivative liabilities	5,756	3,412	35
Designated as Hedging Instrument | Interest Rate Contract | Cash Flow Hedging
Derivative [Line Items]
Derivative assets	3,353	6,270	15,012
Derivative liabilities	2,589	1,656	35
Designated as Hedging Instrument | Interest Rate Contract | Fair Value Hedging
Derivative [Line Items]
Derivative assets	1,260	2,636	4,962
Derivative liabilities	3,167	1,756	0
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative assets	70,891	64,266	58,986
Derivative liabilities	68,112	64,676	55,664
Not Designated as Hedging Instrument | Interest Rate Contract
Derivative [Line Items]
Derivative assets	63,704	59,519	52,996
Derivative liabilities	63,536	59,159	52,408
Not Designated as Hedging Instrument | Interest Rate Lock Commitments
Derivative [Line Items]
Derivative assets	4,387	3,405	5,449
Derivative liabilities	0	2,694	1,207
Not Designated as Hedging Instrument | Forward Commitments to Sell Mortgage Loans
Derivative [Line Items]
Derivative assets	2,416	0	3
Derivative liabilities	4,180	1,486	1,464
Not Designated as Hedging Instrument | Foreign Exchange Contract
Derivative [Line Items]
Derivative assets	384	1,342	538
Derivative liabilities	$ 396	$ 1,337	$ 585