Derivative Financial Instruments (Rollforward Of Amounts In Accumulated Other Comprehensive Income Related To Interest Rate Swaps Designated As Cash Flow Hedges) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Rollforward of AOCI from Cash Flow Hedging Derivatives [Roll Forward]
Amount of (loss) gain recognized in other comprehensive income	$ (4,996)	$ 3,075
Interest Rate Contract
Rollforward of AOCI from Cash Flow Hedging Derivatives [Roll Forward]
Unrealized gain at beginning of period	10,742	11,902
Amount reclassified from accumulated other comprehensive income to interest expense on deposits and other borrowings	(3,562)	(680)
Amount of (loss) gain recognized in other comprehensive income	(1,434)	3,755
Unrealized gain at end of period	$ 5,746	$ 14,977