Noninterest Income Client Investment Fees (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Gains and Losses on Derivatives [Abstract]
Sweep Money Market Fees	$ 12,322	$ 4,396
Investment Advisory, Management and Administrative Fees	5,358	3,378
Sweep Repo Fees	5,195	1,252
Client investment fees	$ 22,875	$ 9,026