Acquisitions (Details) € in Millions, $ in Millions			3 Months Ended	9 Months Ended
	Sep. 03, 2015 USD ($)	Sep. 03, 2015 EUR (€)	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 EUR (€)	Sep. 03, 2015 EUR (€)	Dec. 31, 2014 USD ($)
Business Acquisition [Line Items]
Total cash consideration paid for acquisitions, net of cash acquired				$ 240.7	$ 25.1
Finite-lived intangible assets			$ 180.9	180.9				$ 135.5
Amortization expense 2015			9.7	9.7
Amortization expense 2016			34.9	34.9
Amortization expense 2017			31.8	31.8
Amortization expense 2018			28.7	28.7
Amortization expense 2019			24.1	24.1
Amortization expense 2020			19.6	19.6
Goodwill			1,243.4	1,243.4				1,075.2
Customer relationships
Business Acquisition [Line Items]
Finite-lived intangible assets			172.2	172.2				$ 134.3
7S
Business Acquisition [Line Items]
Total cash consideration paid for acquisitions, net of cash acquired	$ 140.4	€ 125.3
Transaction costs associated with acquisition			2.2	$ 3.4
Net acquired assets	153.0						€ 136.5
Acquired finite-lived intangible assets	49.1	43.8
Goodwill	118.3						€ 105.6
7S | Customer relationships
Business Acquisition [Line Items]
Acquired finite-lived intangible assets	$ 44.2	€ 39.4
Finite-lived intangible assets amortization period				10 years
Finite-lived intangible assets			43.6	$ 43.6		€ 39.0
Amortization expense 2015			1.0	1.0
Amortization expense 2016			4.5	4.5
Amortization expense 2017			4.5	4.5
Amortization expense 2018			4.5	4.5
Amortization expense 2019			4.5	4.5
Amortization expense 2020			$ 4.5	4.5
Series of Individually Immaterial Business Acquisitions
Business Acquisition [Line Items]
Total cash consideration paid for acquisitions, net of cash acquired				$ 100.3	$ 25.1