Derivative Instruments - Gains (Losses) of Derivative Instruments (Details) - Derivatives not designated as hedging instruments: - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Gains (losses) on derivatives financial instruments included in the Consolidated Statements of Income
Gains (losses) on derivative financial instruments	$ 1,847	$ (152)	$ 4,566
Included in interest income on loans | Interest rate contracts
Gains (losses) on derivatives financial instruments included in the Consolidated Statements of Income
Gains (losses) on derivative financial instruments	4,137	3,981	2,402
Included in mortgage banking income | Interest rate lock commitments
Gains (losses) on derivatives financial instruments included in the Consolidated Statements of Income
Gains (losses) on derivative financial instruments	779	356	(2,111)
Included in mortgage banking income | Forward commitments
Gains (losses) on derivatives financial instruments included in the Consolidated Statements of Income
Gains (losses) on derivative financial instruments	$ (3,069)	$ (4,489)	$ 4,275