Premises and Equipment, Net (Summary of Premises and Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 826,947	$ 765,798
Less: Accumulated depreciation and amortization	234,691	210,570
Total premises and equipment, net	592,256	555,228
Land
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	134,030	128,766
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	506,977	470,636
Furniture, equipment, and computer software
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	173,330	160,659
Construction in progress
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 12,610	$ 5,737