Long-Term Debt - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	6 Months Ended					6 Months Ended
	Nov. 30, 2011 D	Sep. 30, 2012	Nov. 22, 2011	Dec. 31, 2011 Federal Funds Effective Rate	Dec. 31, 2011 LIBOR	Dec. 21, 2007 2007 Facility	Sep. 30, 2012 Term Loan	Dec. 31, 2011 Maximum	Dec. 31, 2011 Maximum Eurodollar Rate Loans	Dec. 31, 2011 Maximum Base Rate Loans	Dec. 31, 2011 Minimum	Dec. 31, 2011 Minimum Eurodollar Rate Loans	Dec. 31, 2011 Minimum Base Rate Loans	Nov. 22, 2011 Swing Line Loan Sub-Facility Maximum	Nov. 22, 2011 Letter Of Credit Sub-Facility Maximum
Debt Instrument [Line Items]
Revolving credit facility outstanding amount			$ 250											$ 10	$ 10
Increase in revolving credit facility outstanding amount			300
Term for increase in revolving credit facility before maturity date, days	90
Withdrawal for repayment of existing debt						$ 62
Line of credit facility, maturity		Nov. 21, 2016
Interest rate in excess of effective rate				0.50%
Margin over applicable interest rate (basis point)					100				200	100		125	25
Leverage ratio								2.50			1.00
Line of credit facility period (in years)		5
Interest rate at period end							1.50%
Percentage of capital stock of foreign subsidiaries used as guarantee		65.00%