TREASURY STOCK (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	6 Months Ended
	Mar. 31, 2012	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Equity [Abstract]
Authorized one-time purchase of common stock value	$ 200.0
Repurchase of common stock (in shares)	263,913
Repurchase of common stock aggregate cost	166.2
Remaining authorization of repurchase common stock		459.2
Repurchase of common shares to satisfy employee withholding tax obligations related to stock-based compensation (in shares)		138,171	349,667
Repurchase of common shares to satisfy employee withholding tax obligations related to stock-based compensation		$ 89.0	$ 158.7
Treasury stock, shares (in shares)		8,181,729		7,779,645