Goodwill and Other Intangible Assets (Carrying Value of Intangible Assets Subject to Amortization) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Purchase Value	$ 223,055	$ 234,777
Accumulated Amortization	135,298	127,239
Carrying Value	87,757	107,538
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Purchase Value	190,655	190,655
Accumulated Amortization	113,436	97,026
Carrying Value	77,219	93,629
Credit Card and Trust Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Purchase Value	22,400	22,400
Accumulated Amortization	14,907	12,735
Carrying Value	7,493	9,665
Trade Name [Member]
Finite-Lived Intangible Assets [Line Items]
Purchase Value		11,722
Accumulated Amortization		11,722
Merchant Processing Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Purchase Value	10,000	10,000
Accumulated Amortization	6,955	5,756
Carrying Value	$ 3,045	$ 4,244