Accounting Policies and Basis of Presentation Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2015 USD ($) vote branch	Dec. 31, 2014 USD ($)
Property, Plant and Equipment [Line Items]
Allowance for Loan and Lease Losses, Reserve Release due to Update of Factors	$ 4,800,000
Nonmarketable Securities and Federal Home Loan Bank Stock	$ 37,700,000	$ 52,800,000
Period fair values are subject to refinement	1 year
Number of branches | branch	559
Net deferred fees on non-PCI loans	$ 16,600,000	20,800,000
Baseline for measurement	500,000
Securities Sold under Agreements to Repurchase	622,182,000	324,426,000
Short-term borrowings	$ 594,733,000	$ 987,184,000
Class A Common Stock
Property, Plant and Equipment [Line Items]
Votes per share of common stock | vote	1
Class B Common Stock
Property, Plant and Equipment [Line Items]
Votes per share of common stock | vote	16
Premises | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life of asset	7 years
Premises | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of asset	40 years
Furniture, Software, and Equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life of asset	3 years
Furniture, Software, and Equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of asset	10 years