Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,591,194	$ 1,411,979	$ 1,104,925
Financial Services
Disaggregation of Revenue [Line Items]
Total revenue	1,160,686	1,010,068	734,026
Benefits and Insurance Services
Disaggregation of Revenue [Line Items]
Total revenue	382,605	358,007	332,323
National Practices
Disaggregation of Revenue [Line Items]
Total revenue	47,903	43,904	38,576
Accounting, tax, advisory and consulting
Disaggregation of Revenue [Line Items]
Total revenue	1,160,686	1,010,068	734,026
Accounting, tax, advisory and consulting | Financial Services
Disaggregation of Revenue [Line Items]
Total revenue	1,160,686	1,010,068	734,026
Core Benefits and Insurance Services
Disaggregation of Revenue [Line Items]
Total revenue	365,848	342,063	319,684
Core Benefits and Insurance Services | Benefits and Insurance Services
Disaggregation of Revenue [Line Items]
Total revenue	365,848	342,063	319,684
Non-core Benefits and Insurance Services
Disaggregation of Revenue [Line Items]
Total revenue	16,757	15,944	12,639
Non-core Benefits and Insurance Services | Benefits and Insurance Services
Disaggregation of Revenue [Line Items]
Total revenue	16,757	15,944	12,639
Managed networking, hardware services
Disaggregation of Revenue [Line Items]
Total revenue	36,984	33,503	28,456
Managed networking, hardware services | National Practices
Disaggregation of Revenue [Line Items]
Total revenue	36,984	33,503	28,456
National Practices consulting
Disaggregation of Revenue [Line Items]
Total revenue	10,919	10,401	10,120
National Practices consulting | National Practices
Disaggregation of Revenue [Line Items]
Total revenue	$ 10,919	$ 10,401	$ 10,120