SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Expenses Included in Accrued Expenses and Other Current Liabilities
Accrued online advertising liabilities	$ 69.2	$ 64.3
Accrued compensation liabilities	$ 65.7	$ 54.6
Income Taxes
Likelihood of being realized upon ultimate finalization with taxing authority	greater than 50%