PROPERTIES AND EQUIPMENT Suspended Exploratory Well Costs (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Balance beginning of year, January 1,	$ 19,567	$ 4,432	$ 2,297
Additions to capitalized exploratory well costs pending determination of proved reserves	13,424	30,482	3,692
Reclassifications to wells, facilities and equipment based on the determination of proved reserves	(32,991)	0	(1,557)
capitalized well cost	0	(15,347)	0
Balance end of year, December 31,	0	19,567	4,432
Number of wells pending determination	0	2	6
Aging of Capitalized Exploratory Well Costs
Exploratory well costs capitalized for a period of one year or less		19,567	3,587
Exploratory well costs capitalized for a period greater than one year since commencement of drilling		0	845
Number of projects with exploratory well costs that have been capitalized for a period greater than one year since commencement of drilling		0	2
Southeast Ohio wells
Change in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Additions to capitalized exploratory well costs pending determination of proved reserves		12,200
Rose Run wells
Change in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Additions to capitalized exploratory well costs pending determination of proved reserves		1,200
SECO wells
Change in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Additions to capitalized exploratory well costs pending determination of proved reserves		$ 900