Premises and equipment - Schedule of Premises and Equipment and Related Accumulated Depreciation (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 144,761	$ 136,498
Less: accumulated depreciation	(54,630)	(49,616)
Total Premises and Equipment	90,131	86,882
Land
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	26,283	25,821
Premises
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	65,569	60,995
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	23,545	23,220
Leasehold improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	12,989	11,819
Equipment
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	15,575	13,774
Construction in process
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 800	$ 869

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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