Premises, Equipment and Leases - Components of Premises and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Premises and equipment, total	$ 325,429	$ 289,630
Less accumulated depreciation	(46,330)	(27,106)
Premises and equipment, net of depreciation	279,099	262,524
Buildings
Property, Plant and Equipment [Line Items]
Premises and equipment, total	54,671	31,880
Land improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, total	5,180	3,592
Furniture and equipment
Property, Plant and Equipment [Line Items]
Premises and equipment, total	17,878	10,878
Computers and software
Property, Plant and Equipment [Line Items]
Premises and equipment, total	5,134	665
Leasehold improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, total	8,078	7,757
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	60,947	30,867
Solar panels
Property, Plant and Equipment [Line Items]
Premises and equipment, total	164,295	159,161
Deposits on fixed assets
Property, Plant and Equipment [Line Items]
Premises and equipment, total	$ 596	$ 36,180