Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Assets:
Short-term investments	$ 21.9	$ 26.5
Deferred compensation assets	3.7	3.3
Foreign currency contracts	0.3
Total assets at fair value	25.9	29.8
Liabilities:
Contingent consideration	3.0	2.1
Deferred compensation liabilities	6.9	4.6
Interest rate swap contracts	8.9	8.8
Foreign currency contracts	3.0
Long-term debt	364.7	279.2
Total liabilities at fair value	386.5	294.7
Other Financial Instruments [Abstract]
Long-term debt	362.1	299.3
Level 3 Fair Value Measurements [Roll Forward]
Balance, beginning of period	2.1
Increase in fair value recorded in earnings	0.9
Balance, end of period	3.0
Level 1 [Member]
Assets:
Short-term investments	21.9	26.5
Deferred compensation assets	3.7	3.3
Foreign currency contracts	0
Total assets at fair value	25.6	29.8
Liabilities:
Contingent consideration	0	0
Deferred compensation liabilities	6.9	4.6
Interest rate swap contracts	0	0
Foreign currency contracts	0
Long-term debt	0	0
Total liabilities at fair value	6.9	4.6
Level 2 [Member]
Assets:
Short-term investments	0	0
Deferred compensation assets	0	0
Foreign currency contracts	0.3
Total assets at fair value	0.3	0
Liabilities:
Contingent consideration	0	0
Deferred compensation liabilities	0	0
Interest rate swap contracts	8.9	8.8
Foreign currency contracts	3.0
Long-term debt	364.7	279.2
Total liabilities at fair value	376.6	288.0
Level 3 [Member]
Assets:
Short-term investments	0	0
Deferred compensation assets	0	0
Foreign currency contracts	0
Total assets at fair value	0	0
Liabilities:
Contingent consideration	3.0	2.1
Deferred compensation liabilities	0	0
Interest rate swap contracts	0	0
Foreign currency contracts	0
Long-term debt	0	0
Total liabilities at fair value	$ 3.0	$ 2.1