Premises and Equipment - Components of Premises and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Premises and equipment, total	$ 315,564	$ 325,429
Less accumulated depreciation	(56,297)	(46,330)
Premises and equipment, net of depreciation	259,267	279,099
Buildings
Property, Plant and Equipment [Line Items]
Premises and equipment, total	54,718	54,671
Land improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, total	5,180	5,180
Furniture and equipment
Property, Plant and Equipment [Line Items]
Premises and equipment, total	18,032	17,878
Computers and software
Property, Plant and Equipment [Line Items]
Premises and equipment, total	6,001	5,134
Leasehold improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, total	8,068	8,078
Land
Property, Plant and Equipment [Line Items]
Premises and equipment, total	8,650	8,650
Transportation
Property, Plant and Equipment [Line Items]
Premises and equipment, total	30,496	60,947
Solar panels
Property, Plant and Equipment [Line Items]
Premises and equipment, total	164,295	164,295
Deposits on fixed assets
Property, Plant and Equipment [Line Items]
Premises and equipment, total	$ 20,124	$ 596