Premises and Equipment - Components and Depreciation and Amortization Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Components of premises and equipment
Premises and equipment	$ 571,602	$ 566,822
Less: Accumulated depreciation and amortization	253,154	244,421
Net book value	318,448	322,401
Depreciation and amortization expenses	15,831	15,952	$ 14,522
Occupancy
Components of premises and equipment
Depreciation and amortization expenses	9,149	9,231	9,037
Equipment
Components of premises and equipment
Depreciation and amortization expenses	6,682	6,721	$ 5,485
Buildings
Components of premises and equipment
Premises and equipment	295,286	296,107
Furniture and equipment
Components of premises and equipment
Premises and equipment	95,824	98,800
Land
Components of premises and equipment
Premises and equipment	113,720	114,852
Leasehold improvements
Components of premises and equipment
Premises and equipment	$ 66,772	$ 57,063

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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