Premises and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 488,311	$ 487,012
Less: Accumulated depreciation and amortization	(270,505)	(261,477)
Premises and equipment, net	217,806	225,535
Land
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	36,097	37,380
Buildings and improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	293,836	297,018
Furniture and equipment
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	137,282	136,029
Construction in progress
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 21,096	$ 16,585