Premises and Equipment (Details 1) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Premises and Equipment
Cost	$ 500,488	$ 466,199
Accumulated Depreciation and Amortization	(312,100)	(314,362)
Net Book Value	188,388	151,837
Depreciation and amortization (including capital lease amortization) included in noninterest expense	17,300	14,400	$ 13,000
Premises
Premises and Equipment
Cost	360,170	339,441
Accumulated Depreciation and Amortization	(235,031)	(238,450)
Net Book Value	125,139	100,991
Impairment charge	0	0	$ 0
Equipment
Premises and Equipment
Cost	133,725	120,165
Accumulated Depreciation and Amortization	(72,852)	(71,767)
Net Book Value	60,873	48,398
Finance leases
Premises and Equipment
Cost	6,593	6,593
Accumulated Depreciation and Amortization	(4,217)	(4,145)
Net Book Value	$ 2,376	$ 2,448

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 of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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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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