LONG-TERM DEBT - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Debt Instrument [Line Items]
Revolving credit facility Agreement	London interbank offered rate (“LIBOR”) (as defined) plus 225 basis points or Prime (as defined) plus 125 basis points.
Revolving credit facility		$ 750
Revolving credit facility, interest rate, additional to LIBOR	2.25%
Revolving credit facility, interest rate, additional to Prime	1.25%
Revolving credit facility average interest rate	2.70%
Revolving credit facility, maturity date	2015-12-09
Outstanding letter of credit	5.6
Interest expense	105.5	92.7	88.8
Senior Unsecured Notes 6.875 Percent Due 2020
Debt Instrument [Line Items]
Senior notes, aggregate principal amount	650.0
Debt, interest rate		6.875%
Debt, due date	2020
Senior Unsecured Notes 8.5 Percent Due 2018
Debt Instrument [Line Items]
Senior notes, aggregate principal amount	$ 600.0
Debt, interest rate		8.50%
Debt, due date	2018
Covenant Requirement | Minimum
Debt Instrument [Line Items]
Interest coverage ratio	2.25
Covenant Requirement | Maximum
Debt Instrument [Line Items]
Total leverage ratio	4.25