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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 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	(3,162)	(7,529)	(29,492)	(11,580)
Interest income - loans | Fair Value Hedging | Interest Rate Contracts Two
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized on Derivative	3,162	7,529	29,492	11,580
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	$ (679)	$ 75	$ 364	$ 332