Premises and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Abstract]
Depreciation, Amortization and Accretion, Net	$ 40,700	$ 37,600	$ 32,200
Premises and Equipment [Line Items]
Premises and Equipment, gross	690,224	674,380
Less accumulated depreciation and amortization	370,736	342,083
Premises and Equipment, net	319,488	332,297
Land
Premises and Equipment [Line Items]
Premises and Equipment, gross	57,040	60,397
Buildings
Premises and Equipment [Line Items]
Premises and Equipment, gross	$ 309,754	308,144
Buildings | Minimum
Premises and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	10 years
Buildings | Maximum
Premises and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	35 years
Equipment
Premises and Equipment [Line Items]
Premises and Equipment, gross	$ 182,385	176,906
Equipment | Minimum
Premises and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	3 years
Equipment | Maximum
Premises and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	15 years
Leasehold improvements
Premises and Equipment [Line Items]
Premises and Equipment, gross	$ 24,765	25,151
Leasehold improvements | Minimum
Premises and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	1 year
Leasehold improvements | Maximum
Premises and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	20 years
Software
Premises and Equipment [Line Items]
Premises and Equipment, gross	$ 116,280	$ 103,782
Software | Minimum
Premises and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	3 years
Software | Maximum
Premises and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	7 years