Noninterest Income - Investment Management and Fiduciary Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Trust fees
Revenue from External Customer [Line Items]
Noninterest income	$ 33,288	$ 27,383	$ 23,386
Wealth management and advisory fees
Revenue from External Customer [Line Items]
Noninterest income	15,691	15,067	16,216
Total investment management and fiduciary income
Revenue from External Customer [Line Items]
Noninterest income	$ 48,979	$ 42,450	$ 39,602