Revenues from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 414,762	$ 400,820
United States
Disaggregation of Revenue [Line Items]
Revenues	350,255	335,636
United Kingdom
Disaggregation of Revenue [Line Items]
Revenues	37,183	38,816
Canada
Disaggregation of Revenue [Line Items]
Revenues	11,999	12,387
Ireland
Disaggregation of Revenue [Line Items]
Revenues	15,163	13,697
Other
Disaggregation of Revenue [Line Items]
Revenues	162	284
Investment management fees from pooled investment products
Disaggregation of Revenue [Line Items]
Revenues	116,893	113,771
Investment management fees from investment management agreements
Disaggregation of Revenue [Line Items]
Revenues	96,440	93,409
Investment operations fees
Disaggregation of Revenue [Line Items]
Revenues	106,676	95,243
Investment processing fees - PaaS
Disaggregation of Revenue [Line Items]
Revenues	46,153	43,911
Investment processing fees - SaaS
Disaggregation of Revenue [Line Items]
Revenues	32,420	37,257
Professional services fees
Disaggregation of Revenue [Line Items]
Revenues	3,989	5,194
Account fees and other
Disaggregation of Revenue [Line Items]
Revenues	12,191	12,035
Private Banks
Disaggregation of Revenue [Line Items]
Revenues	113,221	118,259
Private Banks | United States
Disaggregation of Revenue [Line Items]
Revenues	74,014	77,454
Private Banks | United Kingdom
Disaggregation of Revenue [Line Items]
Revenues	24,359	25,350
Private Banks | Canada
Disaggregation of Revenue [Line Items]
Revenues	10,401	10,660
Private Banks | Ireland
Disaggregation of Revenue [Line Items]
Revenues	4,447	4,795
Private Banks | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0
Private Banks | Investment management fees from pooled investment products
Disaggregation of Revenue [Line Items]
Revenues	32,844	32,973
Private Banks | Investment management fees from investment management agreements
Disaggregation of Revenue [Line Items]
Revenues	347	702
Private Banks | Investment operations fees
Disaggregation of Revenue [Line Items]
Revenues	475	376
Private Banks | Investment processing fees - PaaS
Disaggregation of Revenue [Line Items]
Revenues	46,153	43,911
Private Banks | Investment processing fees - SaaS
Disaggregation of Revenue [Line Items]
Revenues	29,169	34,708
Private Banks | Professional services fees
Disaggregation of Revenue [Line Items]
Revenues	2,715	3,777
Private Banks | Account fees and other
Disaggregation of Revenue [Line Items]
Revenues	1,518	1,812
Investment Advisors
Disaggregation of Revenue [Line Items]
Revenues	102,321	94,761
Investment Advisors | United States
Disaggregation of Revenue [Line Items]
Revenues	102,321	94,761
Investment Advisors | United Kingdom
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investment Advisors | Canada
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investment Advisors | Ireland
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investment Advisors | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investment Advisors | Investment management fees from pooled investment products
Disaggregation of Revenue [Line Items]
Revenues	70,180	66,623
Investment Advisors | Investment management fees from investment management agreements
Disaggregation of Revenue [Line Items]
Revenues	27,420	23,838
Investment Advisors | Investment operations fees
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investment Advisors | Investment processing fees - PaaS
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investment Advisors | Investment processing fees - SaaS
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investment Advisors | Professional services fees
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investment Advisors | Account fees and other
Disaggregation of Revenue [Line Items]
Revenues	4,721	4,300
Institutional Investors
Disaggregation of Revenue [Line Items]
Revenues	79,203	80,113
Institutional Investors | United States
Disaggregation of Revenue [Line Items]
Revenues	62,089	62,325
Institutional Investors | United Kingdom
Disaggregation of Revenue [Line Items]
Revenues	12,824	13,466
Institutional Investors | Canada
Disaggregation of Revenue [Line Items]
Revenues	1,598	1,727
Institutional Investors | Ireland
Disaggregation of Revenue [Line Items]
Revenues	2,530	2,311
Institutional Investors | Other
Disaggregation of Revenue [Line Items]
Revenues	162	284
Institutional Investors | Investment management fees from pooled investment products
Disaggregation of Revenue [Line Items]
Revenues	13,317	13,661
Institutional Investors | Investment management fees from investment management agreements
Disaggregation of Revenue [Line Items]
Revenues	65,710	66,171
Institutional Investors | Investment operations fees
Disaggregation of Revenue [Line Items]
Revenues	0	0
Institutional Investors | Investment processing fees - PaaS
Disaggregation of Revenue [Line Items]
Revenues	0	0
Institutional Investors | Investment processing fees - SaaS
Disaggregation of Revenue [Line Items]
Revenues	0	0
Institutional Investors | Professional services fees
Disaggregation of Revenue [Line Items]
Revenues	0	0
Institutional Investors | Account fees and other
Disaggregation of Revenue [Line Items]
Revenues	176	281
Investment Managers
Disaggregation of Revenue [Line Items]
Revenues	116,629	104,649
Investment Managers | United States
Disaggregation of Revenue [Line Items]
Revenues	108,443	98,058
Investment Managers | United Kingdom
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investment Managers | Canada
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investment Managers | Ireland
Disaggregation of Revenue [Line Items]
Revenues	8,186	6,591
Investment Managers | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investment Managers | Investment management fees from pooled investment products
Disaggregation of Revenue [Line Items]
Revenues	193	205
Investment Managers | Investment management fees from investment management agreements
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investment Managers | Investment operations fees
Disaggregation of Revenue [Line Items]
Revenues	106,201	94,867
Investment Managers | Investment processing fees - PaaS
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investment Managers | Investment processing fees - SaaS
Disaggregation of Revenue [Line Items]
Revenues	3,251	2,549
Investment Managers | Professional services fees
Disaggregation of Revenue [Line Items]
Revenues	1,274	1,417
Investment Managers | Account fees and other
Disaggregation of Revenue [Line Items]
Revenues	5,710	5,611
Investments In New Businesses
Disaggregation of Revenue [Line Items]
Revenues	3,388	3,038
Investments In New Businesses | United States
Disaggregation of Revenue [Line Items]
Revenues	3,388	3,038
Investments In New Businesses | United Kingdom
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investments In New Businesses | Canada
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investments In New Businesses | Ireland
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investments In New Businesses | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investments In New Businesses | Investment management fees from pooled investment products
Disaggregation of Revenue [Line Items]
Revenues	359	309
Investments In New Businesses | Investment management fees from investment management agreements
Disaggregation of Revenue [Line Items]
Revenues	2,963	2,698
Investments In New Businesses | Investment operations fees
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investments In New Businesses | Investment processing fees - PaaS
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investments In New Businesses | Investment processing fees - SaaS
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investments In New Businesses | Professional services fees
Disaggregation of Revenue [Line Items]
Revenues	0	0
Investments In New Businesses | Account fees and other
Disaggregation of Revenue [Line Items]
Revenues	$ 66	$ 31