Segment Disclosures - Summary of Disaggregation of Revenue by Source (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 454,606	$ 391,722
Financial Services
Disaggregation of Revenue [Line Items]
Revenue	343,086	288,746
Benefits and Insurance Services
Disaggregation of Revenue [Line Items]
Revenue	100,054	92,486
National Practices
Disaggregation of Revenue [Line Items]
Revenue	11,466	10,490
Accounting, tax, advisory and consulting
Disaggregation of Revenue [Line Items]
Revenue	343,086	288,746
Accounting, tax, advisory and consulting | Financial Services
Disaggregation of Revenue [Line Items]
Revenue	343,086	288,746
Accounting, tax, advisory and consulting | Benefits and Insurance Services
Disaggregation of Revenue [Line Items]
Revenue	0	0
Accounting, tax, advisory and consulting | National Practices
Disaggregation of Revenue [Line Items]
Revenue	0	0
Core benefits and insurance services
Disaggregation of Revenue [Line Items]
Revenue	96,617	88,936
Core benefits and insurance services | Financial Services
Disaggregation of Revenue [Line Items]
Revenue	0	0
Core benefits and insurance services | Benefits and Insurance Services
Disaggregation of Revenue [Line Items]
Revenue	96,617	88,936
Core benefits and insurance services | National Practices
Disaggregation of Revenue [Line Items]
Revenue	0	0
Non-core benefits and insurance services
Disaggregation of Revenue [Line Items]
Revenue	3,437	3,550
Non-core benefits and insurance services | Financial Services
Disaggregation of Revenue [Line Items]
Revenue	0	0
Non-core benefits and insurance services | Benefits and Insurance Services
Disaggregation of Revenue [Line Items]
Revenue	3,437	3,550
Non-core benefits and insurance services | National Practices
Disaggregation of Revenue [Line Items]
Revenue	0	0
Managed networking, hardware services
Disaggregation of Revenue [Line Items]
Revenue	8,954	7,921
Managed networking, hardware services | Financial Services
Disaggregation of Revenue [Line Items]
Revenue	0	0
Managed networking, hardware services | Benefits and Insurance Services
Disaggregation of Revenue [Line Items]
Revenue	0	0
Managed networking, hardware services | National Practices
Disaggregation of Revenue [Line Items]
Revenue	8,954	7,921
National practices consulting
Disaggregation of Revenue [Line Items]
Revenue	2,512	2,569
National practices consulting | Financial Services
Disaggregation of Revenue [Line Items]
Revenue	0	0
National practices consulting | Benefits and Insurance Services
Disaggregation of Revenue [Line Items]
Revenue	0	0
National practices consulting | National Practices
Disaggregation of Revenue [Line Items]
Revenue	$ 2,512	$ 2,569