Derivative Financial Instruments - Derivative Financial Instruments and the Amount and Location of the Net Gains or Losses Recognized in the Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative Instruments Gain Loss [Line Items]
Net gains (losses) recognized in the statements of income	$ 4,578	$ 7,350	$ 14,493	$ 25,348
Interest Rate Lock Commitments | Mortgage Banking Income
Derivative Instruments Gain Loss [Line Items]
Net gains (losses) recognized in the statements of income	2,083	4,903	6,927	15,556
Forward Commitments | Mortgage Banking Income
Derivative Instruments Gain Loss [Line Items]
Net gains (losses) recognized in the statements of income	(53)	(595)	1,598	(3,652)
Interest Rate Swap Agreements | Other Noninterest Income
Derivative Instruments Gain Loss [Line Items]
Net gains (losses) recognized in the statements of income	2,147	2,575	4,848	12,041
Foreign Exchange Contracts | Other Noninterest Income
Derivative Instruments Gain Loss [Line Items]
Net gains (losses) recognized in the statements of income	$ 401	$ 467	$ 1,120	$ 1,403