Revenues from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 400,646	$ 409,586	$ 815,408	$ 810,406
United States
Disaggregation of Revenue [Line Items]
Revenues	340,215	343,519	690,470	679,155
United Kingdom
Disaggregation of Revenue [Line Items]
Revenues	34,625	38,835	71,808	77,651
Canada
Disaggregation of Revenue [Line Items]
Revenues	11,157	12,590	23,156	24,977
Ireland
Disaggregation of Revenue [Line Items]
Revenues	14,516	14,390	29,679	28,087
Other
Disaggregation of Revenue [Line Items]
Revenues	133	252	295	536
Investment management fees from pooled investment products
Disaggregation of Revenue [Line Items]
Revenues	105,963	117,846	222,856	231,617
Investment management fees from investment management agreements
Disaggregation of Revenue [Line Items]
Revenues	92,669	95,520	189,109	188,929
Investment operations fees
Disaggregation of Revenue [Line Items]
Revenues	109,516	100,294	216,192	195,537
Investment processing fees - PaaS
Disaggregation of Revenue [Line Items]
Revenues	44,191	43,156	90,344	87,067
Investment processing fees - SaaS
Disaggregation of Revenue [Line Items]
Revenues	31,439	37,369	63,859	74,626
Professional services fees
Disaggregation of Revenue [Line Items]
Revenues	4,541	4,134	8,530	9,328
Account fees and other
Disaggregation of Revenue [Line Items]
Revenues	12,327	11,267	24,518	23,302
Private Banks
Disaggregation of Revenue [Line Items]
Revenues	107,726	116,092	220,947	234,351
Private Banks | United States
Disaggregation of Revenue [Line Items]
Revenues	71,607	74,889	145,621	152,343
Private Banks | United Kingdom
Disaggregation of Revenue [Line Items]
Revenues	22,345	25,695	46,704	51,045
Private Banks | Canada
Disaggregation of Revenue [Line Items]
Revenues	9,726	10,882	20,127	21,542
Private Banks | Ireland
Disaggregation of Revenue [Line Items]
Revenues	4,048	4,626	8,495	9,421
Private Banks | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Private Banks | Investment management fees from pooled investment products
Disaggregation of Revenue [Line Items]
Revenues	30,307	33,451	63,151	66,424
Private Banks | Investment management fees from investment management agreements
Disaggregation of Revenue [Line Items]
Revenues	292	283	639	985
Private Banks | Investment operations fees
Disaggregation of Revenue [Line Items]
Revenues	438	362	913	738
Private Banks | Investment processing fees - PaaS
Disaggregation of Revenue [Line Items]
Revenues	44,191	43,156	90,344	87,067
Private Banks | Investment processing fees - SaaS
Disaggregation of Revenue [Line Items]
Revenues	28,047	34,776	57,216	69,484
Private Banks | Professional services fees
Disaggregation of Revenue [Line Items]
Revenues	3,157	2,586	5,872	6,363
Private Banks | Account fees and other
Disaggregation of Revenue [Line Items]
Revenues	1,294	1,478	2,812	3,290
Investment Advisors
Disaggregation of Revenue [Line Items]
Revenues	93,708	100,122	196,029	194,883
Investment Advisors | United States
Disaggregation of Revenue [Line Items]
Revenues	93,708	100,122	196,029	194,883
Investment Advisors | United Kingdom
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investment Advisors | Canada
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investment Advisors | Ireland
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investment Advisors | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investment Advisors | Investment management fees from pooled investment products
Disaggregation of Revenue [Line Items]
Revenues	62,251	70,087	132,431	136,710
Investment Advisors | Investment management fees from investment management agreements
Disaggregation of Revenue [Line Items]
Revenues	26,545	25,448	53,965	49,286
Investment Advisors | Investment operations fees
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investment Advisors | Investment processing fees - PaaS
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investment Advisors | Investment processing fees - SaaS
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investment Advisors | Professional services fees
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investment Advisors | Account fees and other
Disaggregation of Revenue [Line Items]
Revenues	4,912	4,587	9,633	8,887
Institutional Investors
Disaggregation of Revenue [Line Items]
Revenues	76,523	81,109	155,726	161,222
Institutional Investors | United States
Disaggregation of Revenue [Line Items]
Revenues	60,414	63,653	122,503	125,978
Institutional Investors | United Kingdom
Disaggregation of Revenue [Line Items]
Revenues	12,280	13,140	25,104	26,606
Institutional Investors | Canada
Disaggregation of Revenue [Line Items]
Revenues	1,431	1,708	3,029	3,435
Institutional Investors | Ireland
Disaggregation of Revenue [Line Items]
Revenues	2,265	2,356	4,795	4,667
Institutional Investors | Other
Disaggregation of Revenue [Line Items]
Revenues	133	252	295	536
Institutional Investors | Investment management fees from pooled investment products
Disaggregation of Revenue [Line Items]
Revenues	12,894	13,799	26,211	27,460
Institutional Investors | Investment management fees from investment management agreements
Disaggregation of Revenue [Line Items]
Revenues	62,924	67,076	128,634	133,247
Institutional Investors | Investment operations fees
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Institutional Investors | Investment processing fees - PaaS
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Institutional Investors | Investment processing fees - SaaS
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Institutional Investors | Professional services fees
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Institutional Investors | Account fees and other
Disaggregation of Revenue [Line Items]
Revenues	705	234	881	515
Investment Managers
Disaggregation of Revenue [Line Items]
Revenues	119,340	109,202	235,969	213,851
Investment Managers | United States
Disaggregation of Revenue [Line Items]
Revenues	111,137	101,794	219,580	199,852
Investment Managers | United Kingdom
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investment Managers | Canada
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investment Managers | Ireland
Disaggregation of Revenue [Line Items]
Revenues	8,203	7,408	16,389	13,999
Investment Managers | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investment Managers | Investment management fees from pooled investment products
Disaggregation of Revenue [Line Items]
Revenues	163	184	356	389
Investment Managers | Investment management fees from investment management agreements
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investment Managers | Investment operations fees
Disaggregation of Revenue [Line Items]
Revenues	109,078	99,932	215,279	194,799
Investment Managers | Investment processing fees - PaaS
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investment Managers | Investment processing fees - SaaS
Disaggregation of Revenue [Line Items]
Revenues	3,392	2,593	6,643	5,142
Investment Managers | Professional services fees
Disaggregation of Revenue [Line Items]
Revenues	1,384	1,548	2,658	2,965
Investment Managers | Account fees and other
Disaggregation of Revenue [Line Items]
Revenues	5,323	4,945	11,033	10,556
Investments In New Businesses
Disaggregation of Revenue [Line Items]
Revenues	3,349	3,061	6,737	6,099
Investments In New Businesses | United States
Disaggregation of Revenue [Line Items]
Revenues	3,349	3,061	6,737	6,099
Investments In New Businesses | United Kingdom
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investments In New Businesses | Canada
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investments In New Businesses | Ireland
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investments In New Businesses | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investments In New Businesses | Investment management fees from pooled investment products
Disaggregation of Revenue [Line Items]
Revenues	348	325	707	634
Investments In New Businesses | Investment management fees from investment management agreements
Disaggregation of Revenue [Line Items]
Revenues	2,908	2,713	5,871	5,411
Investments In New Businesses | Investment operations fees
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investments In New Businesses | Investment processing fees - PaaS
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investments In New Businesses | Investment processing fees - SaaS
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investments In New Businesses | Professional services fees
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Investments In New Businesses | Account fees and other
Disaggregation of Revenue [Line Items]
Revenues	$ 93	$ 23	$ 159	$ 54