DERIVATIVE INSTRUMENTS (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended
	Sep. 30, 2005	Jun. 30, 2014	Dec. 31, 2013
Derivative [Line Items]
Unrealized gains (losses) included in its BGSS related to open financial contracts		$ 1.3	$ 0.7
Initial cost of Treasury Locks	1.4
Amortization period of Treasury Locks	30 years
Unamortized balance of Treasury Locks		$ 1.0	$ 1.0
Basis and Index Related Purchase and Sales Contracts [Member]
Derivative [Line Items]
Outstanding derivative contracts notional amount		0.9
Natural Gas (in MMdts) [Member] | Derivative Transaction Type, Purchase [Member]
Derivative [Line Items]
Outstanding derivative contracts notional amount		9.7
Natural Gas (in MMdts) [Member] | Derivative Transaction Type, Sale [Member]
Derivative [Line Items]
Outstanding derivative contracts notional amount		0.4