Derivative Financial Instruments - Company's derivative financial instruments included in OCI as follows (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Gain in OCI on derivatives	$ 1,485	$ 0	$ 1,485	$ 0
Gain reclassified from OCI into interest income (effective portion)	3,744	8,219	9,042	16,493
Gain recognized in income on derivatives (ineffective portion and amount excluded from effectiveness test)	0	0	0	0
Gain (loss) recognized in other income for foreign currency exchange contracts:	1,584	(1,170)	4,018	4,129
Interest Income
Derivative Instruments, Gain (Loss) [Line Items]
Gain reclassified from OCI into interest income (effective portion)	3,744	8,219	9,042	16,493
Interest Income | Net Investment Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain recognized in income on derivatives (ineffective portion and amount excluded from effectiveness test)	0	0	0	0
Interest Income | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Customer-related positions:	1,427	(1,087)	3,725	3,764
Interest Income | Risk participation agreements
Derivative Instruments, Gain (Loss) [Line Items]
Customer-related positions:	88	(105)	148	264
Other Income
Derivative Instruments, Gain (Loss) [Line Items]
Gain recognized in income on derivatives (ineffective portion and amount excluded from effectiveness test)	0	0	0	0
Other Income | Foreign currency exchange contracts - matched customer book
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in other income for foreign currency exchange contracts:	2	(14)	0	(8)
Other Income | Foreign currency exchange contracts - foreign currency loan
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in other income for foreign currency exchange contracts:	$ 67	$ 36	$ 145	$ 109