Stockholders' Equity - Schedule of Number and Cost of Employee Stock Plan Repurchases (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Equity [Abstract]
Repurchases related to employee stock plans (in shares)	282	62
Repurchases related to employee stock plans	$ 21,680	$ 7,428

Value of shares repurchased in connection with employee stock plans, whereby Company shares were tendered by employees for the payment of applicable withholding taxes and/or exercise price.

No definition available.

Name:	rhi_StockRepurchasedUnderEmployeeStockPlanDuringPeriodValue
Namespace Prefix:	rhi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration