Basis of Presentation and Significant Accounting Policies - Additional Information (Details) $ in Thousands		12 Months Ended
	Nov. 01, 2022 reporting_unit	Dec. 31, 2023 USD ($) practice_group reporting_unit	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of practice groups | practice_group		3
Revenue		$ 1,591,194	$ 1,411,979	$ 1,104,925
Maximum maturity period of investments		3 months
Allowance for doubtful accounts		$ 25,598	20,801	16,158	$ 14,894
Goodwill		865,180	819,917	740,743
Assets		2,043,592	1,879,124
Total stockholders' equity		$ 791,618	713,452	704,548	$ 702,620
Intangible assets amortization period		7 years 4 months 24 days
Number of reporting units | reporting_unit	5	6
Number of reporting units with goodwill balances | reporting_unit		5
Increase (decrease) in the fair value of contingent consideration, net		$ 2,743	2,435	2,367
Unsecured credit facility		600,000
Other income (expense), net
Summary Of Significant Accounting Policies [Line Items]
Increase (decrease) in the fair value of contingent consideration, net		$ 2,700	2,400	2,400
Performance share units
Summary Of Significant Accounting Policies [Line Items]
Shares vesting term		3 years
Minimum
Summary Of Significant Accounting Policies [Line Items]
Shares vesting term		3 years
Intangible assets amortization period		3 years
Minimum | Capitalized software
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life		3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Shares vesting term		4 years
Intangible assets amortization period		15 years
Maximum | Capitalized software
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life		5 years
Financial service
Summary Of Significant Accounting Policies [Line Items]
Revenue		$ 259,600	$ 235,400	$ 174,800