Derivative Financial Instruments (Net gains or losses) (Details 3) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments, Gain (Loss)
Net gains (losses) recognized in the statements of income	$ 6,729	$ 5,091	$ 17,999	$ 8,274
Interest Rate Lock Commitments | Mortgage Banking Income
Derivative Instruments, Gain (Loss)
Net gains (losses) recognized in the statements of income	4,351	3,561	10,654	5,286
Forward Commitments | Mortgage Banking Income
Derivative Instruments, Gain (Loss)
Net gains (losses) recognized in the statements of income	(874)	(1,382)	(3,058)	(1,974)
Interest Rate Swap Agreements | Other Noninterest Income
Derivative Instruments, Gain (Loss)
Net gains (losses) recognized in the statements of income	3,029	1,760	9,467	2,896
Foreign Exchange Contracts | Other Noninterest Income
Derivative Instruments, Gain (Loss)
Net gains (losses) recognized in the statements of income	$ 223	$ 1,152	$ 936	$ 2,066