Derivative Financial Instruments (Rollforward Of Amounts In Accumulated Other Comprehensive Income Related To Interest Rate Swaps Designated As Cash Flow Hedges) (Detail) - Interest Rate Contract - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Rollforward of AOCI from Cash Flow Hedging Derivatives [Roll Forward]
Unrealized (loss) gain at beginning of period	$ (17,943)	$ 10,742
Amount reclassified from accumulated other comprehensive income to interest expense on deposits, other borrowings and junior subordinated debentures	1,090	(3,562)
Amount of loss recognized in other comprehensive income	(39,783)	(1,434)
Unrealized (loss) gain at end of period	$ (56,636)	$ 5,746