Restructuring Costs (Details)	3 Months Ended
	Mar. 31, 2017 USD ($)
Restructuring costs [Abstract]
Net restructuring costs	$ 24,000,000
Restructuring reserve [Roll Forward]
Balance, beginning of period	4,500,000
Costs paid or utilized	(6,600,000)
Severance Costs	15,000,000
Office closure costs and other	9,000,000
Balance, end of period	21,900,000
Reportable segments | Americas
Restructuring reserve [Roll Forward]
Balance, beginning of period	400,000
Costs paid or utilized	(100,000)
Severance Costs	0
Office closure costs and other	0
Balance, end of period	300,000
Reportable segments | Americas | United States | Reportable Subsegments
Restructuring reserve [Roll Forward]
Balance, beginning of period	400,000
Balance, end of period	300,000
Reportable segments | Southern Europe
Restructuring reserve [Roll Forward]
Balance, beginning of period	1,300,000
Costs paid or utilized	0
Severance Costs	0
Office closure costs and other	0
Balance, end of period	1,300,000
Reportable segments | Southern Europe | France | Reportable Subsegments
Restructuring reserve [Roll Forward]
Balance, beginning of period	1,300,000
Balance, end of period	1,300,000
Reportable segments | Southern Europe | Italy | Reportable Subsegments
Restructuring reserve [Roll Forward]
Balance, beginning of period	0
Balance, end of period	0
Reportable segments | Northern Europe
Restructuring reserve [Roll Forward]
Balance, beginning of period	2,600,000
Costs paid or utilized	(5,900,000)
Severance Costs	14,100,000
Office closure costs and other	8,500,000
Balance, end of period	19,300,000
Reportable segments | APME
Restructuring reserve [Roll Forward]
Balance, beginning of period	100,000
Costs paid or utilized	(500,000)
Severance Costs	900,000
Office closure costs and other	500,000
Balance, end of period	1,000,000
Reportable segments | Right Management
Restructuring reserve [Roll Forward]
Balance, beginning of period	100,000
Costs paid or utilized	(100,000)
Severance Costs	0
Office closure costs and other	0
Balance, end of period	0
Corporate
Restructuring reserve [Roll Forward]
Balance, beginning of period	0
Costs paid or utilized	0
Severance Costs	0
Office closure costs and other	0
Balance, end of period	$ 0