Premises and Equipment (Major Classifications) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 1,785,582	$ 1,474,118
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	660,501	597,596
Property, Plant and Equipment, Net	1,125,081	876,522
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	295,090	204,259
Premises and leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,045,718	875,511
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 444,774	$ 394,348