Premises and Equipment - Net of Accumulated Depreciation (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Premises and Equipment, Net of Accumulated Depreciation
Accumulated depreciation	$ (173,647)	$ (159,555)
Net premises and equipment, excluding ROU assets	322,419	272,789
ROU assets	50,178	52,546
Net premises and equipment	372,597	325,335
Land
Premises and Equipment, Net of Accumulated Depreciation
Premises and equipment, gross	75,110	56,842
Buildings and construction in progress
Premises and Equipment, Net of Accumulated Depreciation
Premises and equipment, gross	292,371	259,389
Furniture, Fixtures and Equipment
Premises and Equipment, Net of Accumulated Depreciation
Premises and equipment, gross	113,650	102,749
Leasehold improvements
Premises and Equipment, Net of Accumulated Depreciation
Premises and equipment, gross	$ 14,935	$ 13,364