Premises and Equipment (Major Classifications) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 1,810,954	$ 1,785,582
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	675,125	660,501
Property, Plant and Equipment, Net	1,135,829	1,125,081
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	279,932	284,682
Premises and leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,089,644	1,056,126
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 441,378	$ 444,774