XML 27 R71.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Stock Plans - Stock-Based Compensation Expense (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Restricted stock and stock units |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Total unrecognized compensation cost, net of estimated forfeitures | $ 71.6 | $ 65.6 | $ 62.7

X
- Definition Amount, after tax, of expense for award under share-based payment arrangement. + References No definition available. + Details
Name: | us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardTypeAxis=rhi_RestrictedStockAndStockUnitsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |