Fair Value of Financial Instruments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Dec. 31, 2011
Assets:
Short-term investments	$ 26.4	$ 26.5
Deferred compensation assets	3.6	3.3
Total assets at fair value	30.0	29.8
Liabilities:
Contingent consideration	2.3	2.1
Deferred compensation liabilities	5.4	4.6
Foreign currency contracts	0.5
Interest rate swap contracts	8.2	8.8
Long-term debt	289.5	349.4
Total liabilities at fair value	305.9	15.5
Level 3 Fair Value Measurements [Roll Forward]
Balance, beginning of period	2.1
Increase in fair value recorded in earnings	0.2
Balance, end of period	2.3
Estimate of Fair Value, Fair Value Disclosure [Member]
Other Financial Instruments [Abstract]
Long-term debt	289.5	279.2
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Other Financial Instruments [Abstract]
Long-term debt	294.9	299.3
Level 1 [Member]
Assets:
Short-term investments	26.4	26.5
Deferred compensation assets	3.6	3.3
Total assets at fair value	30.0	29.8
Liabilities:
Contingent consideration	0	0
Deferred compensation liabilities	5.4	4.6
Foreign currency contracts	0
Interest rate swap contracts	0	0
Long-term debt	0
Total liabilities at fair value	5.4	4.6
Level 2 [Member]
Assets:
Short-term investments	0	0
Deferred compensation assets	0	0
Total assets at fair value	0	0
Liabilities:
Contingent consideration	0	0
Deferred compensation liabilities	0	0
Foreign currency contracts	0.5
Interest rate swap contracts	8.2	8.8
Long-term debt	289.5
Total liabilities at fair value	298.2	8.8
Level 3 [Member]
Assets:
Short-term investments	0	0
Deferred compensation assets	0	0
Total assets at fair value	0	0
Liabilities:
Contingent consideration	2.3	2.1
Deferred compensation liabilities	0	0
Foreign currency contracts	0
Interest rate swap contracts	0	0
Long-term debt	0
Total liabilities at fair value	$ 2.3	$ 2.1