Premises and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment
Premises and equipment, gross	$ 422.0	$ 404.2
Less accumulated depreciation	(176.8)	(162.3)
Premises and equipment, net	245.2	241.9
Land
Property, Plant and Equipment
Premises and equipment, gross	49.9	49.4
Buildings and improvements
Property, Plant and Equipment
Premises and equipment, gross	268.1	257.1
Furniture and equipment
Property, Plant and Equipment
Premises and equipment, gross	$ 104.0	$ 97.7

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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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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