MARKETABLE SECURITIES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Proceeds from (Payments for) Trading Securities, Short-term		$ 21.7
Net Realized and Unrealized Gain (Loss) on Trading Securities	$ 0.0	$ 5.6	$ 0.0