Revenue from Contracts with Customers Revenue from Contract with Customers (Schedule of Consumer Brokerage Services) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Consumer Brokerage Services [Line Items]
Consumer brokerage services	$ 3,768	$ 3,649
Non-interest income	119,690	109,613
Commission Income [Member]
Consumer Brokerage Services [Line Items]
Consumer brokerage services	2,092	2,230
Managed Account Services [Member]
Consumer Brokerage Services [Line Items]
Consumer brokerage services	$ 1,676	$ 1,419