Premises and Equipment - Summary of Premises and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Less: accumulated depreciation	$ (69,991)	$ (68,226)
Premises and equipment, net	56,662	64,965
Land
Property, Plant and Equipment [Line Items]
Premises and equipment	10,519	11,219
Buildings
Property, Plant and Equipment [Line Items]
Premises and equipment	43,536	45,321
Furniture and equipment
Property, Plant and Equipment [Line Items]
Premises and equipment	48,127	48,311
Leasehold improvements
Property, Plant and Equipment [Line Items]
Premises and equipment	23,336	26,951
Construction in progress
Property, Plant and Equipment [Line Items]
Premises and equipment	$ 1,135	$ 1,389