Derivative Financial Instruments (Summary Amounts Included In Consolidated Statement Of Income Related To Derivatives) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Interest rate swaps and caps | Trading gains (losses), net
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative instruments	$ 135	$ (75)	$ (996)	$ (392)
Mortgage banking derivatives | Mortgage banking revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative instruments	11,202	1,026	71,761	1,089
Foreign exchange contracts | Trading gains (losses), net
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative instruments	5	54	(8)	72
Covered call options | Fees from covered call options
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative instruments	0	0	2,292	2,427
Derivative contract held as economic hedge on MSRs | Mortgage banking revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative instruments	$ 0	$ 82	$ 4,749	$ 1,002