Reportable Segments Narrative (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2019 segment market	Dec. 31, 2017 segment	Jan. 01, 2018 affiliate
Segment Reporting Information [Line Items]
Document Period End Date	Mar. 31, 2019
Number of reportable segments	3	4
Number of segments combined		2
Private Banking
Segment Reporting Information [Line Items]
Number of geographic markets | market	3
Investment Managers Segment
Segment Reporting Information [Line Items]
Number of consolidated entities | affiliate			2