Summary of Significant Accounting Policies Significant Accounting Policies (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) Locations	Dec. 31, 2017 USD ($)
Locations | Locations	320
Restricted Cash and Cash Equivalents	$ 8,200	$ 12,500
Federal Reserve Bank Reserve Requirement	228,300
Cash Held at Federal Reserve Bank	$ 689,900
Amortization period of annual fees on credit card loans, months	12 months
Period past due loans are placed on non-accrual, days	90 days
Consumer loans charged down to fair value, days delinquent	120 days
Period past due credit card loans are charged off, days	180 days
Common stock dividend rate percentage	5.00%
Accounting Standards Update 2016-01 [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 33,320
Accounting Standards Update 2016-09 [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		$ (1,297)