Premises and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 487,012	$ 522,801
Less: Accumulated depreciation and amortization	(261,477)	(296,774)
Premises and equipment, net	225,535	226,027
Land
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	37,380	37,667
Buildings and improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	297,018	287,271
Furniture and equipment
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	136,029	176,808
Construction in progress
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 16,585	$ 21,055