Restructuring (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Jun. 30, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Description					in connection with a previously announced reduction in force to the Company's workforce of approximately 7% of total staffing, as well as other employee benefit and technology related initiatives. The restructuring is intended to improve the Company's operating efficiency and enhance earnings.	This restructuring was related to the acquisition of Banyan Partners, LLC in 2014.
Restructuring charges	$ 2,100	$ 5,800	$ 900	$ 1,100			$ 7,829	$ 0	$ 2,017
Restructuring costs incurred to date									6,400
Restructuring Reserve [Roll Forward]
Accrued charges, beginning of period				3,305		$ 3,305	337	1,977	3,305
Costs incurred	2,100	$ 5,800	$ 900	1,100			7,829	0	2,017
Costs paid							(3,480)	(1,640)	(3,345)
Accrued charges, end of period	4,686				$ 4,686		4,686	337	1,977
Severance Charges
Restructuring Cost and Reserve [Line Items]
Restructuring charges							5,457	0	2,017
Restructuring Reserve [Roll Forward]
Accrued charges, beginning of period				3,305		3,305	337	1,977	3,305
Costs incurred							5,457	0	2,017
Costs paid							(1,898)	(1,640)	(3,345)
Accrued charges, end of period	3,896				3,896		3,896	337	1,977
Other Associated Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges							2,372	0	0
Restructuring Reserve [Roll Forward]
Accrued charges, beginning of period				$ 0		$ 0	0	0	0
Costs incurred							2,372	0	0
Costs paid							(1,582)	0	0
Accrued charges, end of period	$ 790				$ 790		$ 790	$ 0	$ 0