STANDARDIZED MEASURE OF DISCOUNTED FUTURE NET CASH FLOWS (UNAUDITED) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Estimated cash flows from future production of proved reserves [Abstract]
Future cash inflows	$ 117,560	$ 118,737
Future production costs	(43,641)	(42,213)
Future development cost	(5,022)	(5,148)
Future income taxes	(21,200)	(21,656)
Future net cash flows	47,697	49,720
10% annual discount	(22,597)	(23,807)
Standardized measure of discounted future net cash flows	25,100	25,913
Principal sources of change in the standardized measure of discounted future net cash flows [Roll Forward]
Balance, beginning of year	25,913	17,528
Sales of oil and natural gas produced, net of production costs	(6,914)	(4,662)
Sale of reserves	0	(51)
Extensions and discoveries	3,722	4,112
Net changes in prices and production costs	(2,400)	12,700
Net changes in future development costs	(2,160)	1,137
Revisions and other changes	2,861	(3,659)
Accretion of discount	3,841	2,621
Net change in income taxes	237	(3,813)
Balance, end of year	$ 25,100	$ 25,913
Discount rate used for standardized measure (in hundredths)	10.00%