Long-Term Debt (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2010
Senior credit facility due September 2016
Debt Instrument [Line Items]
Interest rate %	1.80%	1.80%
Long-term debt, Variable rate debt	Libor +1.025 bps and base rate + 0.025%	Libor +1.025 bps and base rate + 0.025%
Long-term debt borrowing capacity	$ 1,000	$ 1,000
Term loan
Debt Instrument [Line Items]
Long-term debt, face amount		215.0
Private Placement notes 5.64 percent, due In 2015
Debt Instrument [Line Items]
Long-term debt, face amount	100.0	100.0
Interest rate %	5.64%	5.64%
Private Placement notes 3.89 percent, due in 2017
Debt Instrument [Line Items]
Long-term debt, face amount	175.0	175.0
Interest rate %	3.89%	3.89%
Private Placement notes 4.47 percent, due in 2020
Debt Instrument [Line Items]
Long-term debt, face amount	$ 225.0	$ 225.0
Interest rate %	4.47%	4.47%
Acquisition notes weighted average rate of 3.0% and weighted average maturity of 4.8 years
Debt Instrument [Line Items]
Debt, maturity years	4.8	4.8
Interest rate %	3.00%	3.00%
Foreign bank debt weighted average rate 6.1% and weighted average maturity of 2.2 years
Debt Instrument [Line Items]
Debt, maturity years	2.2	2.2
Interest rate %	6.10%	6.10%