Accounting Policies and Basis of Presentation - Summary of Significant Accounting Policies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) vote basis_points branch	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jan. 01, 2018 USD ($)
Property, Plant and Equipment [Line Items]
Nonmarketable Securities and Federal Home Loan Bank Stock	$ 25,300	$ 52,700
Period fair values are subject to refinement	1 year
Number of branches | branch	551
Amortization Method Qualified Affordable Housing Project Investments	$ 147,300	128,000
Cumulative effect of new accounting principle in period of adoption				$ (50,051)
Merchant processing		81,300	$ 69,200
Cardholder processing		27,800	20,800
Cardholder Reward Programs		$ 10,000	$ 10,600
Cumulative effect of adoption of ASU 2018-02
Property, Plant and Equipment [Line Items]
Cumulative effect of new accounting principle in period of adoption				0
Cumulative effect of adoption of ASU 2016-01
Property, Plant and Equipment [Line Items]
Cumulative effect of new accounting principle in period of adoption				0
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
Minimum
Property, Plant and Equipment [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 70,000
Maximum
Property, Plant and Equipment [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 80,000
Income tax ASU cumulative effect adjustment [Member] | Cumulative effect of adoption of ASU 2018-02
Property, Plant and Equipment [Line Items]
Cumulative effect of new accounting principle in period of adoption				31,300
Financial Instruments ASU cumulative effect adjustment
Property, Plant and Equipment [Line Items]
Cumulative effect of new accounting principle in period of adoption				$ 18,700
Capital basis points | Minimum
Property, Plant and Equipment [Line Items]
New Accounting Pronouncement or Change in Accounting Principle Effect of Adoption Capital Quantification | basis_points	3
Capital basis points | Maximum
Property, Plant and Equipment [Line Items]
New Accounting Pronouncement or Change in Accounting Principle Effect of Adoption Capital Quantification | basis_points	4