Premises and Equipment, Net - Schedule of Premises and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 214,227	$ 170,092
Accumulated depreciation	(79,478)	(64,588)
Premises and equipment, net	134,749	105,504
Land and land improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	12,356	12,356
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	105,986	71,919
Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	25,694	20,794
Software
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 70,191	$ 65,023