Noninterest Income - Lending Related Fees (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Lending related fees	$ 57,533	$ 49,920	$ 41,949
Unused commitment fees
Disaggregation of Revenue [Line Items]
Lending related fees	42,399	34,829	32,452
Other
Disaggregation of Revenue [Line Items]
Lending related fees	$ 15,134	$ 15,091	$ 9,497