COMMITMENTS AND CONTINGENCIES (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Commitments and Contingencies Disclosure [Abstract]
Minimum initial term of operating lease to be included in commitments and contingencies table (in years)	1 year
Unconditional purchase obligation payments	$ 0.8	$ 0.8	$ 0.8
Net rental payments under non-cancelable operating leases applicable to exploration and development activities and capitalized to oil and gas properties	15.6	21.0	14.0
Net rental payments under non-cancelable operating leases, including compressor rentals, charged to expense	$ 22.0	$ 16.5	$ 18.4