DERIVATIVE FINANCIAL INSTRUMENTS (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2012	Oct. 31, 2011
Derivative [Line Items]
Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net	$ 0.0	$ 0.0	$ 0.0
CashCollateralProvidedByUsToCounterparties	5.6
Cash flow hedges [Abstract]
Commodity forward contracts with Wells Fargo	43.3
Commodity forward contracts with Citibank	20.3
Cash Flow Hedges Derivative Instruments at Fair Value, Net	11.4
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	5.0
Fair value hedges [Abstract]
Notional Amount on Discontinuation of Interest Rate Fair Value Hedge	73.1
Deferred Gain (Loss) on Discontinuation of Interest Rate Fair Value Hedge				$ 2.2
Forward Contracts
Derivative [Line Items]
Derivative, Notional Amount	21.7	0.0
Forward Contracts Sell
Derivative [Line Items]
Derivative, Notional Amount	10.1	0.0
Variable Interest Rate Swaps $125M
Derivative [Line Items]
Derivative, Notional Amount	125.0
Deferred gain recognized	1.2	3.7			$ 11.0
Fixed Interest Rate Swaps $125M
Derivative [Line Items]
Derivative, Notional Amount	125.0
Interest Rate Swaps Designated As Fair Value Hedges
Derivative [Line Items]
Derivative, Notional Amount	$ 0.0	$ 0.0