Derivative Instruments - Gain (loss) recognized on derivatives instruments (Details) - Not designated as hedging - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Gain (loss) recognized on derivative instruments
Gain (loss) recognized on derivatives instruments	$ 1,507	$ (2)	$ (26)
Interest rate lock commitments | Mortgage banking
Gain (loss) recognized on derivative instruments
Gain (loss) recognized on derivatives instruments	1,216	14	70
Forward loan sales commitments | Mortgage banking
Gain (loss) recognized on derivative instruments
Gain (loss) recognized on derivatives instruments	400	$ (16)	$ (96)
TBA mortgage backed securities | Mortgage banking
Gain (loss) recognized on derivative instruments
Gain (loss) recognized on derivatives instruments	$ (109)