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, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Interest rate swaps and caps | Trading gains (losses), net
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative instruments	$ 55	$ 135	$ (56)	$ (996)
Mortgage banking derivatives | Mortgage banking revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative instruments	(4,201)	11,202	(32,160)	71,761
Foreign exchange contracts | Trading gains (losses), net
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative instruments	(1)	5	(9)	(8)
Covered call options | Fees from covered call options
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative instruments	1,157	0	2,545	2,292
Derivative contract held as economic hedge on MSRs | Mortgage banking revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative instruments	$ 0	$ 0	$ 0	$ 4,749