SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Changes in AROs
ARO liability, balance at the end of the period	$ 2,600	$ 13,424
Accrued and other current liabilities
Changes in AROs
ARO liability, balance at the end of the period	8,300
Other non-current liabilities
Changes in AROs
ARO liability, balance at the end of the period	2,600
Natural Gas Storage segment
Changes in AROs
ARO liability, balance at the beginning of the period	13,424	1,212
Increase in ARO liability		12,100
ARO settlements	(1,183)
Accretion expense	123	112
ARO related to Natural Gas Storage disposal group	(1,447)
ARO liability, balance at the end of the period	$ 10,917	$ 13,424