Summary of Significant Accounting Policies - Nature of Operations (Details)	Dec. 31, 2018 country office
Accounting Policies [Abstract]
Number of offices worldwide (nearly) \| office	2,600
Number of countries and territories \| country	80

The number of countries and territories in which the entity operates as of balance sheet date.

No definition available.

Name:	man_NumberOfCountriesAndTerritoriesInWhichEntityOperates
Namespace Prefix:	man_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant