Segment Data - Schedule of Segment Data (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025		Mar. 31, 2024
Segment Reporting Information [Line Items]
Revenues from services	$ 4,090.3		$ 4,403.3	[1]
Cost of Services	3,392.0		3,639.6
Selling and Administrative Expenses	670.1		697.8
Corporate expenses	(41.1)		(41.7)
Intangible asset amortization expense	(8.1)	[2]	(8.3)	[3]
Operating profit	28.2		65.9
Interest and other expenses, net	(11.5)		(8.4)
Earnings before income taxes	16.7		57.5
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues from services	(7.6)		(19.8)	[1]
Cost of Services	(6.5)		(19.8)
Selling and Administrative Expenses	(1.1)		0.0
Operating unit profit	0.0		0.0
United States | Americas
Segment Reporting Information [Line Items]
Revenues from services	688.8		680.4	[4]
Other Americas | Americas
Segment Reporting Information [Line Items]
Revenues from services	367.9		356.0	[4]
France | Southern Europe
Segment Reporting Information [Line Items]
Revenues from services	965.7		1,099.3	[4]
Italy | Southern Europe
Segment Reporting Information [Line Items]
Revenues from services	397.8		404.3	[4]
Other Southern Europe | Southern Europe
Segment Reporting Information [Line Items]
Revenues from services	470.5		477.7	[4]
Reportable subsegments
Segment Reporting Information [Line Items]
Revenues from services	4,090.3		4,403.3
Cost of Services	3,392.0		3,639.6
Selling and Administrative Expenses	620.9		647.8
Operating unit profit	77.4		115.9
Reportable subsegments | Americas
Segment Reporting Information [Line Items]
Revenues from services	1,056.7		1,036.4	[1]
Cost of Services	830.2		798.2
Selling and Administrative Expenses	201.0		212.1
Operating unit profit	25.5		26.1
Reportable subsegments | Southern Europe
Segment Reporting Information [Line Items]
Revenues from services	1,834.0		1,981.3	[1]
Cost of Services	1,565.8		1,687.4	[5]
Selling and Administrative Expenses	218.0		224.0	[5]
Operating unit profit	50.2		69.9	[5]
Reportable subsegments | Northern Europe
Segment Reporting Information [Line Items]
Revenues from services	730.8		870.3	[1]
Cost of Services	604.4		720.3
Selling and Administrative Expenses	144.7		150.0
Operating unit profit	(18.3)		0.0
Reportable subsegments | APME
Segment Reporting Information [Line Items]
Revenues from services	476.4		535.1	[1]
Cost of Services	398.1		453.5
Selling and Administrative Expenses	58.3		61.7
Operating unit profit	20.0		19.9
Reportable subsegments | Northern Europe and APME
Segment Reporting Information [Line Items]
Revenues from services	4,097.9		4,423.1	[1]
Cost of Services	3,398.5		3,659.4
Selling and Administrative Expenses	622.0		647.8
Operating unit profit	77.4		115.9
Reportable subsegments | United States
Segment Reporting Information [Line Items]
Revenues from services	688.8		680.4	[1]
Reportable subsegments | United States | Americas
Segment Reporting Information [Line Items]
Revenues from services	688.8	[6]	680.4	[7]
Cost of Services	517.0	[6]	501.5	[7]
Selling and Administrative Expenses	160.5	[6]	166.9	[7]
Operating unit profit	11.3	[6]	12.0	[7]
Reportable subsegments | Other Americas
Segment Reporting Information [Line Items]
Revenues from services	367.9		356.0	[1]
Reportable subsegments | Other Americas | Americas
Segment Reporting Information [Line Items]
Revenues from services	367.9		356.0
Cost of Services	313.2		296.7
Selling and Administrative Expenses	40.5		45.2
Operating unit profit	14.2		14.1
Reportable subsegments | France | Southern Europe
Segment Reporting Information [Line Items]
Revenues from services	965.7		1,099.3	[1]
Cost of Services	824.8		938.2	[5]
Selling and Administrative Expenses	119.9		128.4	[5]
Operating unit profit	21.0		32.7	[5]
Reportable subsegments | Italy | Southern Europe
Segment Reporting Information [Line Items]
Revenues from services	397.8		404.3	[1]
Cost of Services	333.7		336.4	[5]
Selling and Administrative Expenses	39.5		40.5	[5]
Operating unit profit	24.6		27.4	[5]
Reportable subsegments | Other Southern Europe | Southern Europe
Segment Reporting Information [Line Items]
Revenues from services	470.5		477.7	[1]
Cost of Services	407.3		412.8	[5]
Selling and Administrative Expenses	58.6		55.1	[5]
Operating unit profit	$ 4.6		$ 9.8	[5]

[1] Effective January 1, 2025, our segment reporting was realigned to include our Morocco business within Other Southern Europe. Accordingly, France is now adjusted to exclude Morocco. All previously reported results have been recast to conform to the current year presentation.

[2] Intangible asset amortization related to acquisitions is excluded from operating costs within the reportable segments and corporate expenses and shown separately.

[3] Intangible asset amortization related to acquisitions is excluded from operating costs within the reportable segments and corporate expenses and shown separately.

[4] Effective January 1, 2025, our segment reporting was realigned to include our Morocco business within Other Southern Europe. Accordingly, France is now adjusted to exclude Morocco. All previously reported results have been recast to conform to the current year presentation.

[5] Effective January 1, 2025, our segment reporting was realigned to include our Morocco business within Other Southern Europe. Accordingly, France is now adjusted to exclude Morocco. All previously reported results have been recast to conform to the current year presentation.

[6] The United States revenues above represent revenues from our company-owned branches and franchise fees received from our franchise operations, which were $2.2 for the three months ended March 31, 2025.

[7] The United States revenues above represent revenues from our company-owned branches and franchise fees received from our franchise operations, which were $2.4 for the three months ended March 31, 2024.