Derivatives and Hedging Activities - Gains and losses recognized on derivatives not designated as hedging instruments (Details) - Not designated as hedging instruments - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments [Line Items]
Total gains and losses	$ 1,097	$ 4,413	$ 2,364
Customer derivatives and dealer offsets | Other noninterest income
Derivative Instruments [Line Items]
Total gains and losses	2,878	2,658	2,416
Bifurcated embedded derivatives and dealer offsets | Other noninterest income
Derivative Instruments [Line Items]
Total gains and losses	212	307	429
Interest rate caps | Other noninterest income
Derivative Instruments [Line Items]
Total gains and losses	0	501	252
De-designated hedges | Other noninterest income
Derivative Instruments [Line Items]
Total gains and losses	(193)	31	(62)
Mortgage banking derivatives | Mortgage loan revenue
Derivative Instruments [Line Items]
Total gains and losses	(1,797)	904	(676)
Risk participations | Other noninterest income
Derivative Instruments [Line Items]
Total gains and losses	$ (3)	$ 12	$ 5