Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Assets:
Short-term investments	$ 7.5		$ 12.4
Deferred compensation assets	5.2		4.0
Total assets at fair value	12.7		16.4
Liabilities:
Contingent consideration	3.8		3.3
Deferred compensation liabilities	9.8		7.6
Interest rate swap contracts	6.3		8.6
Foreign currency contracts	1.8		1.4
Total liabilities at fair value	21.7		20.9
Other Financial Instruments [Abstract]
Long-term debt, fair value	383.5		386.0
Long-term debt	381.1		378.8
Level 3 Fair Value Measurements [Roll Forward]
Balance, beginning of period	3.3	2.1
Increase in fair value recorded in earnings	0.5	0.9
Balance, end of period	3.8	3.0
Level 1 [Member]
Assets:
Short-term investments	7.5		12.4
Deferred compensation assets	5.2		4.0
Total assets at fair value	12.7		16.4
Liabilities:
Deferred compensation liabilities	9.8		7.6
Total liabilities at fair value	9.8		7.6
Level 2 [Member]
Liabilities:
Interest rate swap contracts	6.3		8.6
Foreign currency contracts	1.8		1.4
Total liabilities at fair value	8.1		10.0
Level 3 [Member]
Liabilities:
Contingent consideration	3.8		3.3
Total liabilities at fair value	$ 3.8		$ 3.3