FAIR VALUE MEASUREMENTS - Additional Information (Detail) (USD $) In Millions	Jun. 30, 2011		Dec. 31, 2010
Debt Instrument [Line Items]
Fair value of long-term debt, excluding revolving credit agreements	$ 2,691.3		$ 2,747.2
Book value of long-term debt, excluding revolving credit agreements	2,443.7		2,443.5
Revolving credit agreement, amount outstanding	$ 122.0	[1]	$ 53.4

[1] Included within long-term debt