STOCKHOLDERS' EQUITY AND SHARE-BASED COMPENSATION EXPENSE - Stock Options Narrative (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stockholders Equity And Share Based Compensation Expense [Abstract]
Term of historical trend	10 years
Weighted average grant date fair value of options granted (in dollars per share)	$ 4.59	$ 2.42	$ 2.14
Total intrinsic value of options exercised	$ 2.8	$ 0.8	$ 0.1