Derivative Financial Instruments - Effect of Derivative Instruments on Consolidated Statements of Income Derivative in Fair Value Hedging Relationship (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Interest income - loans | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized on Derivative	$ 0	$ 0	$ 0	$ 0
Interest income - loans | Fair Value Hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized on Derivative	1,944	(6,091)	(27,548)	(17,671)
Interest income - loans | Fair Value Hedging | Interest Rate Contracts Two
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized on Derivative	(1,944)	6,091	27,548	17,671
Derivatives not designated as hedging instruments | Other income - gain on sale of loans | Mortgage loan contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized on Derivative	$ 994	$ (429)	$ 1,358	$ (97)