STOCKHOLDERS' EQUITY AND SHARE-BASED COMPENSATION EXPENSE - Stock Options Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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)	$ 5.31	$ 4.59	$ 2.42
Total intrinsic value of options exercised	$ 5.1	$ 2.8	$ 0.8