Derivative Financial Instruments (Schedule Of Fair Value Of Derivative Financial Instruments) (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Derivative [Line Items]
Derivative assets	$ 92,156	$ 52,069	$ 49,703
Derivative liabilities	69,364	35,671	37,651
Interest Rate Contract
Derivative [Line Items]
Derivative assets	86,435	48,985	46,647
Derivative liabilities	64,368	33,716	35,343
Designated as Hedging Instrument
Derivative [Line Items]
Derivative assets	21,767	14,846	10,718
Derivative liabilities	280	12	26
Designated as Hedging Instrument | Interest Rate Contract | Cash Flow Hedging
Derivative [Line Items]
Derivative assets	16,059	11,914	8,644
Derivative liabilities	0	12	0
Designated as Hedging Instrument | Interest Rate Contract | Fair Value Hedging
Derivative [Line Items]
Derivative assets	5,708	2,932	2,074
Derivative liabilities	280	0	26
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative assets	70,389	37,223	38,985
Derivative liabilities	69,084	35,659	37,625
Not Designated as Hedging Instrument | Interest Rate Contract
Derivative [Line Items]
Derivative assets	64,668	34,139	35,929
Derivative liabilities	64,088	33,704	35,317
Not Designated as Hedging Instrument | Interest Rate Lock Commitments
Derivative [Line Items]
Derivative assets	4,543	2,843	2,875
Derivative liabilities	2,512	269	182
Not Designated as Hedging Instrument | Forward Commitments to Sell Mortgage Loans
Derivative [Line Items]
Derivative assets	7	14	78
Derivative liabilities	1,376	1,457	1,961
Not Designated as Hedging Instrument | Foreign Exchange Contract
Derivative [Line Items]
Derivative assets	1,171	227	103
Derivative liabilities	$ 1,108	$ 229	$ 165