Derivative Instruments and Balance Sheet Offsetting - Net Gains (Losses) Related to Changes in Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative instruments
Total gain (loss) recognized in income	$ 512	$ 229	$ 997	$ 738
Forward contracts related to mortgage loans to be delivered for sale | Net gain on sale of loans and other mortgage banking revenue
Derivative instruments
Total gain (loss) recognized in income	(8)	(21)	58	(391)
Interest rate lock commitments | Net gain on sale of loans and other mortgage banking revenue
Derivative instruments
Total gain (loss) recognized in income	929	211	1,638	763
Customer-initiated derivatives | Other noninterest income
Derivative instruments
Total gain (loss) recognized in income	(409)	39	(699)	366
Power Equity CD | Other noninterest income
Derivative instruments
Total gain (loss) recognized in income	$ 0	$ 0	$ 0	$ 0